U.S. patent application number 17/332856 was filed with the patent office on 2021-12-02 for peak reduction tone (prt) selection.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Peter GAAL, Krishna Kiran MUKKAVILLI, June NAMGOONG, Saeid SAHRAEI, Gokul SRIDHARAN.
Application Number | 20210377090 17/332856 |
Document ID | / |
Family ID | 1000005651305 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210377090 |
Kind Code |
A1 |
SAHRAEI; Saeid ; et
al. |
December 2, 2021 |
PEAK REDUCTION TONE (PRT) SELECTION
Abstract
Aspects of the disclosure relate to selection and use of peak
reduction tones (PRTs) including obtaining a predetermined sequence
of PRTs corresponding to a set of granted resources including a
plurality of tones, mapping a set of data to a first subset of the
plurality of tones outside of the predetermined sequence of PRTs
and mapping a set of PRTs to a second subset of the plurality of
tones within the predetermined sequence of PRTs. At least one peak
of a time domain representation of the first subset of the
plurality of tones is canceled using a time domain representation
of the second subset of the plurality of tones. A transmitted
waveform comprising the first subset of the plurality of tones and
the second subset of the plurality of tones is transmitted.
Inventors: |
SAHRAEI; Saeid; (San Diego,
CA) ; SRIDHARAN; Gokul; (Sunnyvale, CA) ;
GAAL; Peter; (San Diego, CA) ; MUKKAVILLI; Krishna
Kiran; (San Diego, CA) ; NAMGOONG; June; (San
Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000005651305 |
Appl. No.: |
17/332856 |
Filed: |
May 27, 2021 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
63031437 |
May 28, 2020 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 27/2614 20130101;
H04L 1/0071 20130101; H04W 72/0446 20130101 |
International
Class: |
H04L 27/26 20060101
H04L027/26; H04W 72/04 20060101 H04W072/04; H04L 1/00 20060101
H04L001/00 |
Claims
1. A method of wireless communication in a wireless communication
network, the method comprising, at a wireless communication
apparatus: obtaining a predetermined sequence of peak reduction
tones (PRTs) corresponding to a set of granted resources comprised
of a plurality of tones; mapping a set of data to a first subset of
the plurality of tones outside of the predetermined sequence of
PRTs; mapping a set of PRTs to a second subset of the plurality of
tones within the predetermined sequence of PRTs; canceling at least
one peak of a time domain representation of the first subset of the
plurality of tones using a time domain representation of the second
subset of the plurality of tones; and transmitting a transmitted
waveform comprising the first subset of the plurality of tones and
the second subset of the plurality of tones.
2. The method of claim 1, wherein only the first subset of the
plurality of tones is intended to be decoded.
3. The method of claim 1, wherein the wireless communication
apparatus is pre-configured with the predetermined sequence of PRTs
corresponding to the set of granted resources.
4. The method of claim 1, wherein the set of granted resources
comprise at least one of: a non-contiguous set of resource blocks,
or a non-contiguous set of subcarriers.
5. The method of claim 1, further comprising: obtaining the
predetermined sequence of PRTs by obtaining a Golomb ruler having
an order that is a function of a total number of tones in the set
of granted resources.
6. The method of claim 1, further comprising obtaining the
predetermined sequence of PRTs by at least one of: obtaining the
predetermined sequence of PRTs from a memory of the wireless
communication apparatus, obtaining the predetermined sequence of
PRTs from a table stored in the memory of the wireless
communication apparatus, or constructing the predetermined sequence
of PRTs from a plurality of PRT-related functions stored in the
memory of the wireless communication apparatus.
7. The method of claim 1, wherein the canceling the at least one
peak of the time domain representation of the first subset of the
plurality of tones using the time domain representation of the
second subset of the plurality of tones, further comprises:
shifting a phase and scaling an amplitude of the time domain
representation of the second subset of the plurality of tones to
align a target peak of the time domain representation of the first
subset of the plurality of tones with a peak of the shifted and
scaled time domain representation of the second subset of the
plurality of tones; subtracting the shifted and scaled time domain
representation of the second subset of the plurality of tones from
the time domain representation of the first subset of the plurality
of tones to obtain a time domain representation of the plurality of
tones; and repeating the shifting, the scaling, and the subtracting
until all peaks of the time domain representation of the plurality
of tones are less than a predefined threshold.
8. The method of claim 1, further comprising, obtaining the
predetermined sequence of PRTs by: determining a number D,
corresponding to a ratio of a number of resource blocks (RBs) in
the set of granted resources to 60 RBs, rounded up to a closest
positive integer; obtaining a set of marks of a Golomb ruler
corresponding to 1/D multiplied by the number of RBs in the set of
granted resources; constructing an initial sequence, r, equal to an
initial PRT sequence corresponding to the Golomb ruler; and
interleaving r with D-1 copies of r to construct the predetermined
sequence of PRTs.
9. The method of claim 1, further comprising, obtaining the
predetermined sequence of PRTs by: determining a number D,
corresponding to a ratio of a number of resource blocks (RBs) in
the set of granted resources to 60 RBs, rounded up to a closest
positive integer; obtaining a set of marks of a Golomb ruler having
an index corresponding to 1/D multiplied by the number of RBs in
the set of granted resources; constructing a sequence, r, based on
the set of marks of the Golomb ruler; and constructing the
predetermined sequence of PRTs (PRTseq(i)), wherein i={1, . . . ,
N} and N is an integer corresponding to a total number of
subcarriers in the set of granted resources, based on: for D=1:
determining a square root, x, of the total number of subcarriers in
the set of granted resources, rounded up to the closest positive
integer; selecting a Golomb ruler of order x, where marks on the
Golomb ruler represent peak reduction tone indices; and
constructing the PRTseq(i) as a sequence of zeros and ones of
length equal to the total number of subcarriers, wherein PRTseq(i)
is equal to 1 at the peak reduction tone indices and zero
otherwise; for .times. .times. D = 2 : .times. PRTseq .function. (
i ) = { r .function. ( i 2 ) .times. .times. if .times. .times. mod
.function. ( i , 2 ) = 0 r .function. ( i - 1 2 ) .times. .times.
if .times. .times. mod .function. ( i , 2 ) = 1 ; .times. for
.times. .times. D = 3 : .times. PRTseq .function. ( i ) = { r
.function. ( i 3 ) .times. .times. if .times. .times. mod
.function. ( i , 3 ) = 0 r .function. ( i - 1 3 ) .times. .times.
if .times. .times. mod .function. ( i , 3 ) = 1 r .function. ( i -
2 3 ) .times. .times. if .times. .times. mod .function. ( i , 3 ) =
2 ; .times. for .times. .times. D = 4 : .times. PRTseq .function. (
i ) = { r .function. ( i 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 0 r .function. ( i - 1 4 ) .times. .times.
if .times. .times. mod .function. ( i , 4 ) = 1 r .function. ( i -
2 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
2 r .function. ( i - 3 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 3 ; and .times. .times. for .times. .times.
D = 5 : .times. PRTseq .function. ( i ) = { r .function. ( i 5 )
.times. .times. if .times. .times. mod .function. ( i , 5 ) = 0 r
.function. ( i - 1 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 1 r .function. ( i - 2 5 ) .times. .times.
if .times. .times. mod .function. ( i , 5 ) = 2 r .function. ( i -
3 5 ) .times. .times. if .times. .times. mod .function. ( i , 5 ) =
3 r .function. ( i - 4 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 4 . ##EQU00018##
10. A wireless communication apparatus in a wireless communication
network, comprising: a wireless transceiver; a memory; and a
processor coupled to the wireless transceiver and the memory,
wherein the processor and the memory are configured to: obtain a
predetermined sequence of peak reduction tones (PRTs) corresponding
to a set of granted resources comprised of a plurality of tones;
map a set of data to a first subset of the plurality of tones
outside of the predetermined sequence of PRTs; map a set of PRTs to
a second subset of the plurality of tones within the predetermined
sequence of PRTs; cancel at least one peak of a time domain
representation of the first subset of the plurality of tones using
a time domain representation of the second subset of the plurality
of tones; and transmit a transmitted waveform comprising the first
subset of the plurality of tones and the second subset of the
plurality of tones.
11. The wireless communication apparatus of claim 10, wherein only
the first subset of the plurality of tones is intended to be
decoded.
12. The wireless communication apparatus of claim 10, wherein the
wireless communication apparatus is pre-configured with the
predetermined sequence of PRTs associated with the set of granted
resources.
13. The wireless communication apparatus of claim 10, wherein the
set of granted resources comprises at least one of: a
non-contiguous set of resource blocks, or a non-contiguous set of
subcarriers.
14. The wireless communication apparatus of claim 10, wherein the
processor and the memory are further configured to obtain the
predetermined sequence of PRTs by obtaining a Golomb ruler having
an order that is a function of a total number of tones in the set
of granted resources.
15. The wireless communication apparatus of claim 10, wherein the
processor and the memory are further configured to obtain the
predetermined sequence of PRTs by being further configured to at
least one of: obtain the predetermined sequence of PRTs from a
memory of the wireless communication apparatus, obtain the
predetermined sequence of PRTs from a table stored in the memory of
the wireless communication apparatus, or construct the
predetermined sequence of PRTs from a plurality of PRT-related
functions stored in the memory of the wireless communication
apparatus.
16. The wireless communication apparatus of claim 10, wherein the
processor and the memory are configured to cancel the at least one
peak of the time domain representation of the first subset of the
plurality of tones using the time domain representation of the
second subset of the plurality of tones by being further configured
to: shift a phase and scale an amplitude of the time domain
representation of the second subset of the plurality of tones to
align a target peak of the time domain representation of the first
subset of the plurality of tones with a peak of the shifted and
scaled time domain representation of the second subset of the
plurality of tones; subtract the shifted and scaled time domain
representation of the second subset of the plurality of tones from
the time domain representation of the first subset of the plurality
of tones to obtain a time domain representation of the plurality of
tones; and repeat the shifting, the scaling, and the subtracting
until all peaks of the time domain representation of the plurality
of tones are less than a predefined threshold.
17. The wireless communication apparatus of claim 10, wherein the
processor and the memory are configured to obtain the predetermined
sequence of PRTs by being further configured to: determine a number
D, corresponding to a ratio of a number of resource blocks (RBs) in
the set of granted resources to 60 RBs, rounded up to a closest
positive integer; obtain a set of marks of a Golomb ruler having an
index corresponding to 1/D multiplied by the number of RBs in the
set of granted resources; construct an initial sequence, r, equal
to an initial PRT sequence corresponding to the Golomb ruler; and
interleave r with D-1 copies of r to construct the predetermined
sequence of PRTs.
18. The wireless communication apparatus of claim 10, wherein the
processor and the memory are configured to obtain the predetermined
sequence of PRTs by being further configured to: determine a number
D, corresponding to a ratio of a number of resource blocks (RBs) in
the set of granted resources to 60 RBs, rounded up to a closest
positive integer; obtain a set of marks of a Golomb ruler
corresponding to 1/D multiplied by the number of RBs in the set of
granted resources; construct a sequence, r, based on the set of
marks of the Golomb ruler; and construct the predetermined sequence
of PRTs (PRTseq(i)), wherein i={1, . . . , N} and N is an integer
corresponding to a total number of subcarriers in the set of
granted resources, based on: for .times. .times. D = 1 :
##EQU00019## determine a square root, x, of the total number of
subcarriers in the set of granted resources, rounded up to the
closest positive integer; select a Golomb ruler of order x, where
marks on the Golomb ruler represent peak reduction tone indices;
and construct the PRTseq(i), as a sequence of zeros and ones of
length equal to the total number of subcarriers, wherein PRTseq(i)
is equal to 1 at the peak reduction tone indices and zero
otherwise; for .times. .times. D = 2 : .times. PRTseq .function. (
i ) = { r .function. ( i 2 ) .times. .times. if .times. .times. mod
.function. ( i , 2 ) = 0 r .function. ( i - 1 2 ) .times. .times.
if .times. .times. mod .function. ( i , 2 ) = 1 ; .times. for
.times. .times. D = 3 : .times. PRTseq .function. ( i ) = { r
.function. ( i 3 ) .times. .times. if .times. .times. mod
.function. ( i , 3 ) = 0 r .function. ( i - 1 3 ) .times. .times.
if .times. .times. mod .function. ( i , 3 ) = 1 r .function. ( i -
2 3 ) .times. .times. if .times. .times. mod .function. ( i , 3 ) =
2 ; .times. for .times. .times. D = 4 : .times. PRTseq .function. (
i ) = { r .function. ( i 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 0 r .function. ( i - 1 4 ) .times. .times.
if .times. .times. mod .function. ( i , 4 ) = 1 r .function. ( i -
2 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
2 r .function. ( i - 3 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 3 ; and .times. .times. for .times. .times.
D = 5 : .times. PRTseq .function. ( i ) = { r .function. ( i 5 )
.times. .times. if .times. .times. mod .function. ( i , 5 ) = 0 r
.function. ( i - 1 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 1 r .function. ( i - 2 5 ) .times. .times.
if .times. .times. mod .function. ( i , 5 ) = 2 r .function. ( i -
3 5 ) .times. .times. if .times. .times. mod .function. ( i , 5 ) =
3 r .function. ( i - 4 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 4 . ##EQU00020##
19. A wireless communication apparatus in a wireless communication
network, comprising: means for obtaining a predetermined sequence
of peak reduction tones (PRTs) corresponding to a set of granted
resources comprised of a plurality of tones; means for mapping a
set of data to a first subset of the plurality of tones outside of
the predetermined sequence of PRTs; means for mapping a set of PRTs
to a second subset of the plurality of tones within the
predetermined sequence of PRTs; means for canceling at least one
peak of a time domain representation of the first subset of the
plurality of tones using a time domain representation of the second
subset of the plurality of tones; and means for transmitting a
transmitted waveform comprising the first subset of the plurality
of tones and the second subset of the plurality of tones.
20. The wireless communication apparatus of claim 19, wherein only
the first subset of the plurality of tones is intended to be
decoded.
21. The wireless communication apparatus of claim 19, wherein the
means for obtaining the predetermined sequence of PRTs further
comprise at least one of: means for obtaining the predetermined
sequence of PRTs from a memory of the wireless communication
apparatus, means for obtaining the predetermined sequence of PRTs
from a table stored in the memory of the wireless communication
apparatus, or means for constructing the predetermined sequence of
PRTs from a plurality of PRT-related functions stored in the memory
of the wireless communication apparatus.
22. The wireless communication apparatus of claim 19, wherein the
means for canceling at least one peak of the time domain
representation of the first subset of the plurality of tones using
the time domain representation of the second subset of the
plurality of tones further comprises: means for shifting a phase
and scaling an amplitude of the time domain representation of the
second subset of the plurality of tones to align a target peak of
the time domain representation of the first subset of the plurality
of tones with a peak of the shifted and scaled time domain
representation of the second subset of the plurality of tones;
means for subtracting the shifted and scaled time domain
representation of the second subset of the plurality of tones from
the time domain representation of the first subset of the plurality
of tones to obtain a time domain representation of the plurality of
tones; and means for repeating the shifting, the scaling, and the
subtracting until all peaks of the time domain representation of
the plurality of tones are less than a predefined threshold.
23. An article of manufacture for use by a wireless communication
apparatus in a wireless communication network, the article
comprising: a non-transitory computer-readable medium having stored
therein instructions executable by one or more processors of the
wireless communication apparatus to: obtain a predetermined
sequence of peak reduction tones (PRTs) corresponding to a set of
granted resources comprised of a plurality of tones; map a set of
data to a first subset of the plurality of tones outside of the
predetermined sequence of PRTs; map a set of PRTs to a second
subset of the plurality of tones within the predetermined sequence
of PRTs; cancel at least one peak of a time domain representation
of the first subset of the plurality of tones using a time domain
representation of the second subset of the plurality of tones; and
transmit a transmitted waveform comprising the first subset of the
plurality of tones and the second subset of the plurality of
tones.
24. The article of manufacture of claim 23, wherein only the first
subset of the plurality of tones is intended to be decoded.
25. The article of manufacture of claim 23, wherein the
instructions executable by one or more processors of the wireless
communication apparatus further comprises instructions to obtain
the predetermined sequence of PRTs by at least one of: obtaining
the predetermined sequence of PRTs from a memory of the wireless
communication apparatus, obtaining the predetermined sequence of
PRTs from a table stored in the memory of the wireless
communication apparatus, or constructing the predetermined sequence
of PRTs from a plurality of PRT-related functions stored in the
memory of the wireless communication apparatus.
26. The article of manufacture of claim 23, wherein the
instructions executable by one or more processors of the wireless
communication apparatus to cancel the at least one peak of the time
domain representation of the first subset of the plurality of tones
using the time domain representation of the second subset of the
plurality of tones, further comprises instructions to: shift a
phase and scale an amplitude of the time domain representation of
the second subset of the plurality of tones to align a target peak
of the time domain representation of the first subset of the
plurality of tones with a peak of the shifted and scaled time
domain representation of the second subset of the plurality of
tones; subtract the shifted and scaled time domain representation
of the second subset of the plurality of tones from the time domain
representation of the first subset of the plurality of tones to
obtain a time domain representation of the plurality of tones; and
repeat the shifting, the scaling, and the subtracting until all
peaks of the time domain representation of the plurality of tones
are less than a predefined threshold.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application for patent claims priority to and the
benefit of provisional patent application No. 63/031,437 entitled
"Method and Apparatus for Selection of Peak Reduction Tones (PRTs)
Based on Optimal Golomb Rulers" filed in the United States Patent
and Trademark Office on May 28, 2020, the entire content of which
is incorporated herein by reference as if fully set forth below in
its entirety and for all applicable purposes.
TECHNICAL FIELD
[0002] The technology discussed below relates generally to wireless
communication systems, and more particularly, to avoiding
non-linearity in power amplifiers by selection of peak reduction
tones (PRTs).
INTRODUCTION
[0003] Power amplifiers, including commercial power amplifiers,
have a non-linear behavior if operated at input power levels at or
greater than their 1 dB compression point levels. This
non-linearity results in in-band and out-of-band distortion of an
input signal and degraded error vector management (EVM) at the
receiver. EVM is a measure of modulation accuracy, or how well a
power amplifier is transmitting information, represented by varying
phase and amplitude of a radio frequency (RF) signal. To avoid the
non-linearity, a power amplifier may be operated at a mean input
power level that is several dB lower than the saturation point of
the power amplifier. Operation at the mean input power level may
involve an input back off (IBO) of x dB in examples where an input
signal has a peak-to-average power ratio (PAPR) of x dB to avoid
non-linearity due to the peak of the input signal.
[0004] Orthogonal frequency-division multiplexed (OFDM) signals are
known to suffer from significant PAPR that grows rapidly as the
number of resource blocks increases. For example, 5G new radio (NR)
may allow higher data rates than long term evolution (LTE). The
higher data rates may result in an increased OFDM resource block
size, thereby increasing the PAPR. Existing PAPR reduction
techniques are data-dependent and computationally expensive, making
them undesirable for real-time implementation. As a result,
clipping and filtering (CF) is a common way to reduce PAPR in the
industry. However, CF may result in in-band distortion and may not
converge to a desirable solution.
BRIEF SUMMARY OF SOME EXAMPLES
[0005] The following presents a summary of one or more aspects of
the present disclosure, in order to provide a basic understanding
of such aspects. This summary is not an extensive overview of all
contemplated features of the disclosure and is intended neither to
identify key or critical elements of all aspects of the disclosure
nor to delineate the scope of any or all aspects of the disclosure.
Its sole purpose is to present some concepts of one or more aspects
of the disclosure in a form as a prelude to the more detailed
description that is presented later.
[0006] In one example, a method of wireless communication is
disclosed. The method includes obtaining a predetermined sequence
of peak reduction tones (PRTs) corresponding to a set of resources
(e.g., a set of granted/assigned resources) comprised of a
plurality of tones, mapping a set of data to a first subset of the
plurality of tones outside of the predetermined sequence of PRTs,
mapping a set of PRTs to a second subset of the plurality of tones
within the predetermined sequence of PRTs, canceling at least one
peak of a time domain representation of the first subset of the
plurality of tones using a time domain representation of the second
subset of the plurality of tones, and transmitting a transmitted
waveform comprising the first subset of the plurality of tones and
the second subset of the plurality of tones.
[0007] In another example, a wireless communication apparatus is
disclosed. The wireless communication apparatus includes a wireless
transceiver, a memory, and a processor coupled to the wireless
transceiver and the memory. In one example the processor and the
memory may be configured to obtain a predetermined sequence of peak
reduction tones (PRTs) corresponding to a set of resources
comprised of a plurality of tones, map a set of data to a first
subset of the plurality of tones outside of the predetermined
sequence of PRTs, map a set of PRTs to a second subset of the
plurality of tones within the predetermined sequence of PRTs,
cancel at least one peak of a time domain representation of the
first subset of the plurality of tones using a time domain
representation of the second subset of the plurality of tones, and
transmit a transmitted waveform comprising the first subset of the
plurality of tones and the second subset of the plurality of
tones.
[0008] According to one aspect, a wireless communication apparatus
may include means for obtaining a predetermined sequence of peak
reduction tones (PRTs) corresponding to a set of resources
comprised of a plurality of tones, means for mapping a set of data
to a first subset of the plurality of tones outside of the
predetermined sequence of PRTs, means for mapping a set of PRTs to
a second subset of the plurality of tones within the predetermined
sequence of PRTs, means for canceling at least one peak of a time
domain representation of the first subset of the plurality of tones
using a time domain representation of the second subset of the
plurality of tones, and means for transmitting a transmitted
waveform comprising the first subset of the plurality of tones and
the second subset of the plurality of tones.
[0009] In still another example, an article of manufacture for use
by a wireless communication apparatus in a wireless communication
network is disclosed. In the example, the article of manufacture
may include a non-transitory computer-readable medium having stored
therein instructions executable by one or more processors of the
wireless communication apparatus. The instructions executable by
one or more processors of the wireless communication apparatus may
include instructions to obtain a predetermined sequence of peak
reduction tones (PRTs) corresponding to a set of resources
comprised of a plurality of tones, map a set of data to a first
subset of the plurality of tones outside of the predetermined
sequence of PRTs, map a set of PRTs to a second subset of the
plurality of tones within the predetermined sequence of PRTs,
cancel at least one peak of a time domain representation of the
first subset of the plurality of tones using a time domain
representation of the second subset of the plurality of tones, and
transmit a transmitted waveform comprising the first subset of the
plurality of tones and the second subset of the plurality of
tones.
[0010] These and other aspects will become more fully understood
upon a review of the detailed description, which follows. Other
aspects, features, and examples will become apparent to those of
ordinary skill in the art upon reviewing the following description
of specific exemplary aspects in conjunction with the accompanying
figures. While features may be discussed relative to certain
examples and figures below, all examples can include one or more of
the advantageous features discussed herein. In other words, while
one or more examples may be discussed as having certain
advantageous features, one or more of such features may also be
used in accordance with the various examples discussed herein.
Similarly, while examples may be discussed below as device, system,
or method examples, it should be understood that such examples can
be implemented in various devices, systems, and methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic illustration of a wireless
communication system according to some aspects of the
disclosure.
[0012] FIG. 2 is a schematic illustration of an example of a radio
access network (RAN) according to some aspects of the
disclosure.
[0013] FIG. 3 is an expanded view of an exemplary subframe, showing
an orthogonal frequency divisional multiplexing (OFDM) resource
grid according to some aspects of the disclosure.
[0014] FIG. 4A is a diagram illustrating an example AM-to-AM
conversion curve for a solid state power amplifier according to
some aspects of the disclosure.
[0015] FIGS. 4B, 4C, and 4D are representations of the graph of
FIG. 4A according to some aspects of the disclosure.
[0016] FIG. 5 is a plot of data tones and peak reduction tones in
the frequency domain according to some aspects of the
disclosure.
[0017] FIG. 6 is a plot of data tones and peak reduction tones in
the time domain according to some aspects of the disclosure.
[0018] FIGS. 7A, 7B, and 7C are diagrams illustrating example time
domain representations of various inverse fast Fourier transforms
(IFFTs) of respective sets of reserved tones according to some
aspects of the disclosure.
[0019] FIG. 8 depicts an imperfect kernel and a perfect kernel
according to some aspects of the disclosure.
[0020] FIG. 9 is a diagram of an example representation of an RF
signal in the frequency domain including 31 tones (subcarriers),
where 25 of the tones are data tones and 6 of the tones are peak
reduction tones (PRTs) according to some aspects of the
disclosure.
[0021] FIG. 10A is a diagram illustrating the cumulative
distribution function (CCDF) of peak-to-average power ratio (PAPR)
per symbol for the RF signal of 31 tones illustrated in FIG. 9
according to some aspects of the disclosure.
[0022] FIG. 10B is a diagram illustrating the CCDF of PAPR per tone
for the same RF signal of 31 tones illustrated in FIG. 9 according
to some aspects of the disclosure.
[0023] FIG. 11 is a block diagram illustrating an example of a
hardware implementation of a wireless communication apparatus
employing a processing system according to some aspects of the
disclosure.
[0024] FIG. 12 is a flow chart illustrating an exemplary process at
a wireless communication apparatus for wireless communication
according to some aspects of the disclosure.
[0025] FIG. 13 is a flow chart illustrating another exemplary
process at a wireless communication apparatus for wireless
communication according to some aspects of the disclosure.
DETAILED DESCRIPTION
[0026] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details. In some instances, well known structures and components
are shown in block diagram form in order to avoid obscuring such
concepts.
[0027] While aspects and examples are described in this application
by illustration to some examples, those skilled in the art will
understand that additional implementations and use cases may come
about in many different arrangements and scenarios. Innovations
described herein may be implemented across many differing platform
types, devices, systems, shapes, sizes, and packaging arrangements.
For example, aspects and/or uses may come about via integrated chip
examples and other non-module-component-based devices (e.g.,
end-user devices, vehicles, communication devices, computing
devices, industrial equipment, retail/purchasing devices, medical
devices, AI-enabled devices, etc.). While some examples may or may
not be specifically directed to use cases or applications, a wide
assortment of applicability of described innovations may occur.
Implementations may range in spectrum from chip-level or modular
components to non-modular, non-chip-level implementations and
further to aggregate, distributed, or original equipment
manufacturer (OEM) devices or systems incorporating one or more
aspects of the described innovations. In some practical settings,
devices incorporating described aspects and features may also
necessarily include additional components and features for the
implementation and practice of claimed and described examples. For
example, transmission and reception of wireless signals necessarily
includes a number of components for analog and digital purposes
(e.g., hardware components including antenna, RF-chains, power
amplifiers, modulators, buffer, processor(s), interleaver,
adders/summers, etc.). It is intended that innovations described
herein may be practiced in a wide variety of devices, chip-level
components, systems, distributed arrangements, end-user devices,
etc., of varying sizes, shapes, and constitution.
[0028] According to aspects described herein, peak reduction tone
(PRT) techniques may be used to reduce a peak-to-average power
ratio (PAPR) of transmitted signals. To reduce computational
complexity, for example, a location of a sequence of PRTs may be
determined and fixed in advance of a time when PRT techniques are
implemented. If fixed in advance, a receiver will know which tones,
of a plurality of received tones transmitted from a transmitter,
are PRTs and which tones are data. The receiver may then decode
only the data tones. By fixing in advance the PRT sequences,
resources may be saved as a transmitter may not need to inform the
receiver of the location of the PRTs used by the transmitter.
[0029] In addition, when the locations of the PRTs of a PRT
sequence are fixed in advance, a transmitter may perform a
non-computationally complex optimization of the phase and magnitude
of the tones in the PRT sequence to minimize the PAPR of a
transmitted signal. Furthermore, fixing the PRT sequence in
advance, and pre-configuring the transmitter and receiver to be
aware of a specific PRT sequence used for a given set of resources,
may reduce the overall computational complexity of using PRT
techniques to reduce the PAPR of a transmitted signal. For ease of
reference, a set of resources, whether assigned or granted, will be
interchangeably referred to throughout as either a set of resources
or a set of granted resources.
[0030] The electromagnetic spectrum is often subdivided, based on
frequency/wavelength, into various classes, bands, channels, etc.
In 5G NR two initial operating bands have been identified as
frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25
GHz-52.6 GHz). It should be understood that although a portion of
FR1 is greater than 6 GHz, FR1 is often referred to
(interchangeably) as a "Sub-6 GHz" band in various documents and
articles. A similar nomenclature issue sometimes occurs with regard
to FR2, which is often referred to (interchangeably) as a
"millimeter wave" band in documents and articles, despite being
different from the extremely high frequency (EHF) band (30 GHz-300
GHz) which is identified by the International Telecommunications
Union (ITU) as a "millimeter wave" band.
[0031] The frequencies between FR1 and FR2 are often referred to as
mid-band frequencies. Recent 5G NR studies have identified an
operating band for these mid-band frequencies as frequency range
designation FR3 (7.125 GHz-24.25 GHz). Frequency bands falling
within FR3 may inherit FR1 characteristics and/or FR2
characteristics, and thus may effectively extend features of FR1
and/or FR2 into mid-band frequencies. In addition, higher frequency
bands are currently being explored to extend 5G NR operation beyond
52.6 GHz. For example, three higher operating bands have been
identified as frequency range designations FR4-a or FR4-1 (52.6
GHz-71 GHz), FR4 (52.6 GHz-114.25 GHz), and FR5 (114.25 GHz-300
GHz). Each of these higher frequency bands falls within the EHF
band.
[0032] With the above aspects in mind, unless specifically stated
otherwise, it should be understood that the term "sub-6 GHz" or the
like if used herein may broadly represent frequencies that may be
less than 6 GHz, may be within FR1, or may include mid-band
frequencies. Further, unless specifically stated otherwise, it
should be understood that the term "millimeter wave" or the like if
used herein may broadly represent frequencies that may include
mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1,
and/or FR5, or may be within the EHF band.
[0033] While aspects and examples are described in this application
by illustration to some examples, those skilled in the art will
understand that additional implementations and use cases may come
about in many different arrangements and scenarios. Innovations
described herein may be implemented across many differing platform
types, devices, systems, shapes, sizes, and packaging arrangements.
For example, aspects and/or uses may come about via integrated chip
examples and other non-module-component-based devices (e.g.,
end-user devices, vehicles, communication devices, computing
devices, industrial equipment, retail/purchasing devices, medical
devices, AI-enabled devices, etc.). While some examples may or may
not be specifically directed to use cases or applications, a wide
assortment of applicability of described innovations may occur.
Implementations may range in spectrum from chip-level or modular
components to non-modular, non-chip-level implementations and
further to aggregate, distributed, or original equipment
manufacturer (OEM) devices or systems incorporating one or more
aspects of the described innovations. In some practical settings,
devices incorporating described aspects and features may also
necessarily include additional components and features for
implementation and practice of claimed and described examples. For
example, transmission and reception of wireless signals necessarily
includes a number of components for analog and digital purposes
(e.g., hardware components including antenna, RF-chains, power
amplifiers, modulators, buffer, processor(s), interleaver,
adders/summers, etc.). It is intended that innovations described
herein may be practiced in a wide variety of devices, chip-level
components, systems, distributed arrangements, end-user devices,
etc., of varying sizes, shapes, and constitution.
[0034] The various concepts presented throughout this disclosure
may be implemented across a broad variety of telecommunication
systems, network architectures, and communication standards.
Referring now to FIG. 1, as an illustrative example without
limitation, various aspects of the present disclosure are
illustrated with reference to a wireless communication system 100.
The wireless communication system 100 includes three interacting
domains: a core network 102, a radio access network (RAN) 104, and
a user equipment (UE) 106. By virtue of the wireless communication
system 100, the UE 106 may be enabled to carry out data
communication with an external data network 110, such as (but not
limited to) the Internet.
[0035] The RAN 104 may implement any suitable wireless
communication technology or technologies to provide radio access to
the UE 106. As one example, the RAN 104 may operate according to
3rd Generation Partnership Project (3GPP) New Radio (NR)
specifications, often referred to as 5G. As another example, the
RAN 104 may operate under a hybrid of 5G NR and Evolved Universal
Terrestrial Radio Access Network (eUTRAN) standards, often referred
to as Long Term Evolution (LTE). The 3GPP refers to this hybrid RAN
as a next-generation RAN, or NG-RAN. Of course, many other examples
may be utilized within the scope of the present disclosure.
[0036] As illustrated, the RAN 104 includes a plurality of base
stations 108. Broadly, a base station is a network element in a
radio access network responsible for radio transmission and
reception in one or more cells to or from a UE. In different
technologies, standards, or contexts, a base station may variously
be referred to by those skilled in the art as a base transceiver
station (BTS), a radio base station, a radio transceiver, a
transceiver function, a basic service set (BSS), an extended
service set (ESS), an access point (AP), a Node B (NB), an eNode B
(eNB), a gNode B (gNB), a transmission and reception point (TRP),
or some other suitable terminology. In some examples, a base
station may include two or more TRPs that may be collocated or
non-collocated. Each TRP may communicate on the same or different
carrier frequency within the same or different frequency band. In
examples where the RAN 104 operates according to both the LTE and
5G NR standards, one of the base stations may be an LTE base
station, while another base station may be a 5G NR base
station.
[0037] The RAN 104 is further illustrated supporting wireless
communication for multiple mobile apparatuses. A mobile apparatus
may be referred to as user equipment (UE) in 3GPP standards, but
may also be referred to by those skilled in the art as a mobile
station (MS), a subscriber station, a mobile unit, a subscriber
unit, a wireless unit, a remote unit, a mobile device, a wireless
device, a wireless communication device, a remote device, a mobile
subscriber station, an access terminal (AT), a mobile terminal, a
wireless terminal, a remote terminal, a handset, a terminal, a user
agent, a mobile client, a client, or some other suitable
terminology. A UE may be an apparatus (e.g., a mobile apparatus)
that provides a user with access to network services.
[0038] Within the present disclosure, a "mobile" apparatus need not
necessarily have a capability to move and may be stationary. The
term mobile apparatus or mobile device broadly refers to a diverse
array of devices and technologies. UEs may include a number of
hardware structural components sized, shaped, and arranged to help
in communication; such components can include antennas, antenna
arrays, RF-chains, amplifiers, one or more processors, etc.
electrically coupled to each other. For example, some non-limiting
examples of a mobile apparatus include a mobile, a cellular (cell)
phone, a smart phone, a session initiation protocol (SIP) phone, a
laptop, a personal computer (PC), a notebook, a netbook, a
smartbook, a tablet, a personal digital assistant (PDA), and a
broad array of embedded systems, e.g., corresponding to an
"Internet of things" (IoT).
[0039] A mobile apparatus may additionally be an automotive or
other transportation vehicle, a remote sensor or actuator, a robot
or robotics device, a satellite radio, a global positioning system
(GPS) device, an object tracking device, a drone, a multi-copter, a
quad-copter, a remote control device, a consumer and/or wearable
device, such as eyewear, a wearable camera, a virtual reality
device, a smart watch, a health or fitness tracker, a digital audio
player (e.g., MP3 player), a camera, a game console, etc. A mobile
apparatus may additionally be a digital home or smart home device
such as a home audio, video, and/or multimedia device, an
appliance, a vending machine, intelligent lighting, a home security
system, a smart meter, etc. A mobile apparatus may additionally be
a smart energy device, a security device, a solar panel or solar
array, a municipal infrastructure device controlling electric power
(e.g., a smart grid), lighting, water, etc., an industrial
automation and enterprise device, a logistics controller, and/or
agricultural equipment, etc. Still further, a mobile apparatus may
provide for connected medicine or telemedicine support, e.g.,
health care at a distance. Telehealth devices may include
telehealth monitoring devices and telehealth administration
devices, whose communication may be given preferential treatment or
prioritized access over other types of information, e.g., in terms
of prioritized access for transport of critical service data,
and/or relevant QoS for transport of critical service data.
[0040] Wireless communication between the RAN 104 and the UE 106
may be described as utilizing an air interface. Transmissions over
the air interface from a base station (e.g., base station 108) to
one or more UEs (e.g., similar to UE 106) may be referred to as
downlink (DL) transmission. In accordance with certain aspects of
the present disclosure, the term downlink may refer to a
point-to-multipoint transmission originating at a base station
(e.g., base station 108). Another way to describe this scheme may
be to use the term broadcast channel multiplexing. Transmissions
from a UE (e.g., UE 106) to a base station (e.g., base station 108)
may be referred to as uplink (UL) transmissions. In accordance with
further aspects of the present disclosure, the term uplink may
refer to a point-to-point transmission originating at a UE (e.g.,
UE 106).
[0041] In some examples, access to the air interface may be
scheduled, wherein a scheduling entity (e.g., a base station 108)
allocates resources for communication among some or all devices and
equipment within its service area or cell. Within the present
disclosure, as discussed further below, the scheduling entity may
be responsible for scheduling, assigning, reconfiguring, and
releasing resources for one or more scheduled entities (e.g., UEs
106). That is, for scheduled communication, a plurality of UEs 106,
which may be scheduled entities, may utilize resources allocated by
the scheduling entity 108.
[0042] Base stations 108 are not the only entities that may
function as scheduling entities. That is, in some examples, a UE
may function as a scheduling entity, scheduling resources for one
or more scheduled entities (e.g., one or more other UEs). For
example, UEs may communicate directly with other UEs in a
peer-to-peer or device-to-device fashion and/or in a relay
configuration.
[0043] As illustrated in FIG. 1, a scheduling entity 108 may
broadcast downlink traffic 112 to one or more scheduled entities
(e.g., one or more UEs 106). Broadly, the scheduling entity 108 is
a node or device responsible for scheduling traffic in a wireless
communication network, including the downlink traffic 112 and, in
some examples, uplink traffic 116 from one or more scheduled
entities (e.g., one or more UEs 106) to the scheduling entity 108.
On the other hand, the scheduled entity (e.g., a UE 106) is a node
or device that receives downlink control information 114, including
but not limited to scheduling information (e.g., a grant),
synchronization or timing information, or other control information
from another entity in the wireless communication network such as
the scheduling entity 108.
[0044] In addition, the uplink and/or downlink control information
and/or traffic information may be transmitted on a waveform that
may be time-divided into frames, subframes, slots, and/or symbols.
As used herein, a symbol may refer to a unit of time that, in an
orthogonal frequency division multiplexed (OFDM) waveform, carries
one resource element (RE) per sub-carrier. A slot may carry 7 or 14
OFDM symbols. A subframe may refer to a duration of 1 ms. Multiple
subframes or slots may be grouped together to form a single frame
or radio frame. Within the present disclosure, a frame may refer to
a predetermined duration (e.g., 10 ms) for wireless transmissions,
with each frame consisting of, for example, 10 subframes of 1 ms
each. Of course, these definitions are not required, and any
suitable scheme for organizing waveforms may be utilized, and
various time divisions of the waveform may have any suitable
duration.
[0045] In general, base stations 108 may include a backhaul
interface for communication with a backhaul portion 120 of the
wireless communication system 100. The backhaul portion 120 may
provide a link between a base station 108 and the core network 102.
Further, in some examples, a backhaul network may provide
interconnection between the respective base stations 108. Various
types of backhaul interfaces may be employed, such as a direct
physical connection, a virtual network, or the like using any
suitable transport network.
[0046] The core network 102 may be a part of the wireless
communication system 100 and may be independent of the radio access
technology used in the RAN 104. In some examples, the core network
102 may be configured according to 5G standards (e.g., 5GC). In
other examples, the core network 102 may be configured according to
a 4G evolved packet core (EPC), or any other suitable standard or
configuration.
[0047] Referring now to FIG. 2, as an illustrative example without
limitation, a schematic illustration of a radio access network
(RAN) 200 according to some aspects of the present disclosure is
provided. In some examples, the RAN 200 may be the same as the RAN
104 described above and illustrated in FIG. 1.
[0048] The geographic region covered by the RAN 200 may be divided
into a number of cellular regions (cells) that can be uniquely
identified by a user equipment (UE) based on an identification
broadcasted over a geographical area from one access point or base
station. FIG. 2 illustrates cells 202, 204, 206, and 208, each of
which may include one or more sectors (not shown). A sector is a
sub-area of a cell. All sectors within one cell are served by the
same base station. A radio link within a sector can be identified
by a single logical identification belonging to that sector. In a
cell that is divided into sectors, the multiple sectors within a
cell can be formed by groups of antennas with each antenna
responsible for communication with UEs in a portion of the
cell.
[0049] Various base station arrangements can be utilized. For
example, in FIG. 2, two base stations, base station 210 and base
station 212 are shown in cells 202 and 204. A third base station,
base station 214 is shown controlling a remote radio head (RRH) 216
in cell 206. That is, a base station can have an integrated antenna
or can be connected to an antenna or RRH 216 by feeder cables. In
the illustrated example, cells 202, 204, and 206 may be referred to
as macrocells, as the base stations 210, 212, and 214 support cells
having a large size. Further, a base station 218 is shown in the
cell 208, which may overlap with one or more macrocells. In this
example, the cell 208 may be referred to as a small cell (e.g., a
small cell, a microcell, picocell, femtocell, home base station,
home Node B, home eNode B, etc.), as the base station 218 supports
a cell having a relatively small size. Cell sizing can be done
according to system design as well as component constraints.
[0050] It is to be understood that the RAN 200 may include any
number of wireless base stations and cells. Further, a relay node
may be deployed to extend the size or coverage area of a given
cell. The base stations 210, 212, 214, 218 provide wireless access
points to a core network for any number of mobile apparatuses. In
some examples, the base stations 210, 212, 214, and/or 218 may be
the same as or similar to the scheduling entity 108 described above
and illustrated in FIG. 1.
[0051] FIG. 2 further includes an unmanned aerial vehicle (UAV)
220, which may be a drone or quadcopter. The UAV 220 may be
configured to function as a base station, or more specifically as a
mobile base station. That is, in some examples, a cell may not
necessarily be stationary, and the geographic area of the cell may
move according to the location of a mobile base station, such as
the UAV 220.
[0052] Within the RAN 200, the cells may include UEs that may be in
communication with one or more sectors of each cell. Further, each
base station 210, 212, 214, 218, and 220 may be configured to
provide an access point to a core network 102 (see FIG. 1) for all
the UEs in the respective cells. For example, UEs 222 and 224 may
be in communication with base station 210; UEs 226 and 228 may be
in communication with base station 212; UEs 230 and 232 may be in
communication with base station 214 by way of RRH 216; UE 234 may
be in communication with base station 218; and UE 236 may be in
communication with mobile base station 220. In some examples, the
UEs 222, 224, 226, 228, 230, 232, 234, 236, 238, 240, and/or 242
may be the same as or similar to the UE/scheduled entity 106
described above and illustrated in FIG. 1. In some examples, the
UAV 220 (e.g., the quadcopter) can be a mobile network node and may
be configured to function as a UE. For example, the UAV 220 may
operate within cell 202 by communicating with base station 210.
[0053] In a further aspect of the RAN 200, sidelink signals may be
used between UEs without necessarily relying on scheduling or
control information from a base station. Sidelink communication may
be utilized, for example, in a device-to-device (D2D) network,
peer-to-peer (P2P) network, vehicle-to-vehicle (V2V) network,
vehicle-to-everything (V2X) network, and/or other suitable sidelink
network. For example, two or more UEs (e.g., UEs 238, 240, and 242)
may communicate with each other using sidelink signals 237 without
relaying that communication through a base station. In some
examples, the UEs 238, 240, and 242 may each function as a
scheduling entity or transmitting sidelink device and/or a
scheduled entity or a receiving sidelink device to schedule
resources and communicate sidelink signals 237 therebetween without
relying on scheduling or control information from a base station.
In other examples, two or more UEs (e.g., UEs 226 and 228) within
the coverage area of a base station (e.g., base station 212) may
also communicate sidelink signals 227 over a direct link (sidelink)
without conveying that communication through the base station 212.
In this example, the base station 212 may allocate resources to the
UEs 226 and 228 for the sidelink communication.
[0054] In order for transmissions over the air interface to obtain
a low block error rate (BLER) while still achieving very high data
rates, channel coding may be used. That is, wireless communication
may generally utilize a suitable error correcting block code. In a
typical block code, an information message or sequence is split up
into code blocks (CBs), and an encoder (e.g., a CODEC) at the
transmitting device then mathematically adds redundancy to the
information message. Exploitation of this redundancy in the encoded
information message can improve the reliability of the message,
enabling correction for any bit errors that may occur due to the
noise.
[0055] Data coding may be implemented in multiple manners. In early
5G NR specifications, user data is coded using quasi-cyclic
low-density parity check (LDPC) with two different base graphs: one
base graph is used for large code blocks and/or high code rates,
while the other base graph is used otherwise. Control information
and the physical broadcast channel (PBCH) are coded using Polar
coding, based on nested sequences. For these channels, puncturing,
shortening, and repetition are used for rate matching.
[0056] Aspects of the present disclosure may be implemented
utilizing any suitable channel code. Various implementations of
base stations and UEs may include suitable hardware and
capabilities (e.g., an encoder, a decoder, and/or a CODEC) to
utilize one or more of these channel codes for wireless
communication.
[0057] In the RAN 200, the ability of UEs to communicate while
moving, independent of their location, is referred to as mobility.
The various physical channels between the UE and the RAN 200 are
generally set up, maintained, and released under the control of an
access and mobility management function (AMF). In some scenarios,
the AMF may include a security context management function (SCMF)
and a security anchor function (SEAF) that performs authentication.
The SCMF can manage, in whole or in part, the security context for
both the control plane and the user plane functionality.
[0058] In various aspects of the disclosure, the RAN 200 may
utilize DL-based mobility or UL-based mobility to enable mobility
and handovers (i.e., the transfer of a UE's connection from one
radio channel to another). In a network configured for DL-based
mobility, during a call with a scheduling entity, or at any other
time, a UE may monitor various parameters of the signal from its
serving cell as well as various parameters of neighboring cells.
Depending on the quality of these parameters, the UE may maintain
communication with one or more of the neighboring cells. During
this time, if the UE moves from one cell to another, or if signal
quality from a neighboring cell exceeds that from the serving cell
for a given amount of time, the UE may undertake a handoff or
handover from the serving cell to the neighboring (target) cell.
For example, the UE 224 may move from the geographic area
corresponding to its serving cell 202 to the geographic area
corresponding to a neighbor cell 206. When the signal strength or
quality from the neighbor cell 206 exceeds that of its serving cell
202 for a given amount of time, the UE 224 may transmit a reporting
message to its serving base station 210 indicating this condition.
In response, the UE 224 may receive a handover command, and the UE
may undergo a handover to the cell 206.
[0059] In a network configured for UL-based mobility, UL reference
signals from each UE may be utilized by the network to select a
serving cell for each UE. In some examples, the base stations 210,
212, and 214/216 may broadcast unified synchronization signals
(e.g., unified Primary Synchronization Signals (PSSs), unified
Secondary Synchronization Signals (SSSs) and unified Physical
Broadcast Channels (PBCH)). The UEs 222, 224, 226, 228, 230, and
232 may receive the unified synchronization signals, derive the
carrier frequency, and slot timing from the synchronization
signals, and in response to deriving timing, transmit an uplink
pilot or reference signal. The uplink pilot signal transmitted by a
UE (e.g., UE 224) may be concurrently received by two or more cells
(e.g., base stations 210 and 214/216) within the RAN 200. Each of
the cells may measure a strength of the pilot signal, and the radio
access network (e.g., one or more of the base stations 210 and
214/216 and/or a central node within the core network) may
determine a serving cell for the UE 224. As the UE 224 moves
through the RAN 200, the RAN 200 may continue to monitor the uplink
pilot signal transmitted by the UE 224. When the signal strength or
quality of the pilot signal measured by a neighboring cell exceeds
that of the signal strength or quality measured by the serving
cell, the RAN 200 may handover the UE 224 from the serving cell to
the neighboring cell, with or without informing the UE 224.
[0060] Although the synchronization signal transmitted by the base
stations 210, 212, and 214/216 may be unified, the synchronization
signal may not identify a particular cell, but rather may identify
a zone of multiple cells operating on the same frequency and/or
with the same timing. The use of zones in 5G networks or other next
generation communication networks enables the uplink-based mobility
framework and improves the efficiency of both the UE and the
network, since the number of mobility messages that need to be
exchanged between the UE and the network may be reduced.
[0061] In various implementations, the air interface in the radio
access network 200 may utilize licensed spectrum, unlicensed
spectrum, or shared spectrum. Licensed spectrum provides for
exclusive use of a portion of the spectrum, generally by virtue of
a mobile network operator purchasing a license from a government
regulatory body. Unlicensed spectrum provides for shared use of a
portion of the spectrum without need for a government-granted
license. While compliance with some technical rules is generally
still required to access unlicensed spectrum, generally, any
operator or device may gain access. Shared spectrum may fall
between licensed and unlicensed spectrum, wherein technical rules
or limitations may be required to access the spectrum, but the
spectrum may still be shared by multiple operators and/or multiple
RATs. For example, the holder of a license for a portion of
licensed spectrum may provide licensed shared access (LSA) to share
that spectrum with other parties, e.g., with suitable
licensee-determined conditions to gain access.
[0062] Devices communicating in the radio access network 200 may
utilize one or more multiplexing techniques and multiple access
algorithms to enable simultaneous communication of the various
devices. For example, 5G NR specifications provide multiple access
for UL transmissions from UEs 222 and 224 to base station 210, and
for multiplexing for DL transmissions from base station 210 to one
or more UEs 222 and 224, utilizing orthogonal frequency division
multiplexing (OFDM) with a cyclic prefix (CP). In addition, for UL
transmissions, 5G NR specifications provide support for discrete
Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP (also referred
to as single-carrier FDMA (SC-FDMA)). However, within the scope of
the present disclosure, multiplexing and multiple access are not
limited to the above schemes, and may be provided utilizing time
division multiple access (TDMA), code division multiple access
(CDMA), frequency division multiple access (FDMA), sparse code
multiple access (SCMA), resource spread multiple access (RSMA), or
other suitable multiple access schemes. Further, multiplexing DL
transmissions from the base station 210 to UEs 222 and 224 may be
provided utilizing time division multiplexing (TDM), code division
multiplexing (CDM), frequency division multiplexing (FDM),
orthogonal frequency division multiplexing (OFDM), sparse code
multiplexing (SCM), or other suitable multiplexing schemes.
[0063] Devices in the radio access network 200 may also utilize one
or more duplexing algorithms Duplex refers to a point-to-point
communication link where both endpoints can communicate with one
another in both directions. Full-duplex means both endpoints can
simultaneously communicate with one another. Half-duplex means only
one endpoint can send information to the other at a time.
Half-duplex emulation is frequently implemented for wireless links
utilizing time division duplex (TDD). In TDD, transmissions in
different directions on a given channel are separated from one
another using time division multiplexing. That is, in some
scenarios, a channel is dedicated for transmissions in one
direction, while at other times the channel is dedicated for
transmissions in the other direction, where the direction may
change very rapidly, e.g., several times per slot. In a wireless
link, a full-duplex channel generally relies on physical isolation
of a transmitter and receiver, and suitable interference
cancellation technologies. Full-duplex emulation is frequently
implemented for wireless links by utilizing frequency division
duplex (FDD) or spatial division duplex (SDD). In FDD,
transmissions in different directions may operate at different
carrier frequencies (e.g., within paired spectrum). In SDD,
transmissions in different directions on a given channel are
separated from one another using spatial division multiplexing
(SDM). In other examples, full-duplex communication may be
implemented within unpaired spectrum (e.g., within a single carrier
bandwidth), where transmissions in different directions occur
within different sub-bands of the carrier bandwidth. This type of
full-duplex communication may be referred to herein as sub-band
full-duplex (SBFD), also known as flexible duplex.
[0064] Various aspects of the present disclosure will be described
with reference to an OFDM waveform, schematically illustrated in
FIG. 3. It should be understood by those of ordinary skill in the
art that the various aspects of the present disclosure may be
applied to an SC-FDMA waveform in substantially the same way as
described hereinbelow. That is, while some examples of the present
disclosure may focus on an OFDM link for clarity, it should be
understood that the same principles may be applied as well to
SC-FDMA waveforms.
[0065] Referring now to FIG. 3, an expanded view of an exemplary
subframe 302 is illustrated, showing an OFDM resource grid
according to some aspects of the disclosure. However, as those
skilled in the art will readily appreciate, the physical (PHY)
transmission structure for any particular application may vary from
the example described here, depending on any number of factors.
Here, time is in the horizontal direction with units of OFDM
symbols; and frequency is in the vertical direction with units of
subcarrier of the carrier.
[0066] The resource grid 304 may be used to schematically represent
time-frequency resources for a given antenna port. That is, in a
multiple-input-multiple-output (MIMO) implementation with multiple
antenna ports available, a corresponding multiple number of
resource grids 304 may be available for communication. The resource
grid 304 is divided into multiple resource elements (REs) 306. An
RE, which is 1 subcarrier.times.1 symbol, is the smallest discrete
part of the time-frequency grid, and contains a single complex
value representing data from a physical channel or signal.
Depending on the transmission and reception scheme utilized in a
particular implementation, each RE may represent one or more bits
of information. In some examples, a block of REs may be referred to
as a physical resource block (PRB) or more simply a resource block
(RB) 308, which contains any suitable number of consecutive
subcarriers in the frequency domain. In one example, an RB may
include 12 subcarriers, a number independent of the numerology
used. In some examples, depending on the numerology, an RB may
include any suitable number of consecutive OFDM symbols in the time
domain. Within the present disclosure, it is assumed that a single
RB such as the RB 308 entirely corresponds to a single direction of
communication (either transmission or reception for a given
device).
[0067] A set of continuous or discontinuous resource blocks may be
referred to herein as a Resource Block Group (RBG), sub-band, or
bandwidth part (BWP). A set of sub-bands or BWPs may span the
entire bandwidth. Scheduling of scheduled entities (e.g., UEs) for
downlink, uplink, or sidelink transmissions typically involves
scheduling one or more resource elements 306 within one or more
sub-bands or bandwidth parts (BWPs). Thus, a UE generally utilizes
only a subset of the resource grid 304. In some examples, an RB may
be the smallest unit of resources that can be allocated to a UE.
Thus, the more RBs scheduled for a UE, and the higher the
modulation scheme chosen for the air interface, the higher the data
rate for the UE. The RBs may be scheduled by a scheduling entity,
such as a base station (e.g., gNB, eNB, etc.), or may be
self-scheduled by a UE implementing D2D sidelink communication.
[0068] In this illustration, the RB 308 is shown as occupying less
than the entire bandwidth of the subframe 302, with some
subcarriers illustrated above and below the RB 308. In a given
implementation, the subframe 302 may have a bandwidth corresponding
to any number of one or more RBs 308. Further, in this
illustration, the RB 308 is shown as occupying less than the entire
duration of the subframe 302, although this is merely one possible
example.
[0069] Each 1 ms subframe 302 may consist of one or multiple
adjacent slots. In the example shown in FIG. 3, one subframe 302
includes four slots 310, as an illustrative example. In some
examples, a slot may be defined according to a specified number of
OFDM symbols with a given cyclic prefix (CP) length. For example, a
slot may include 7 or 14 OFDM symbols with a nominal CP. Additional
examples may include mini-slots, sometimes referred to as shortened
transmission time intervals (TTIs), having a shorter duration
(e.g., one to three OFDM symbols). These mini-slots or shortened
transmission time intervals (TTIs) may in some cases be transmitted
occupying resources scheduled for ongoing slot transmissions for
the same or for different UEs. Any number of resource blocks may be
utilized within a subframe or slot.
[0070] An expanded view of one of the slots 310 illustrates the
slot 310 including a control region 312 and a data region 314. In
general, the control region 312 may carry control channels, and the
data region 314 may carry data channels. Of course, a slot may
contain all DL, all UL, or at least one DL portion and at least one
UL portion. The structure illustrated in FIG. 3 is merely exemplary
in nature, and different slot structures may be utilized, and may
include one or more of each of the control region(s) and data
region(s).
[0071] Although not illustrated in FIG. 3, the various REs 306
within an RB 308 may be scheduled to carry one or more physical
channels, including control channels, shared channels, data
channels, etc. Other REs 306 within the RB 308 may also carry
pilots or reference signals. These pilots or reference signals may
provide for a receiving device to perform channel estimation of the
corresponding channel, which may enable coherent
demodulation/detection of the control and/or data channels within
the RB 308.
[0072] In some examples, the slot 310 may be utilized for
broadcast, multicast, groupcast, or unicast communication. For
example, a broadcast, multicast, or groupcast communication may
refer to a point-to-multipoint transmission by one device (e.g., a
base station, UE, or other similar device) to other devices. Here,
a broadcast communication is delivered to all devices, whereas a
multicast or groupcast communication is delivered to multiple
intended recipient devices. A unicast communication may refer to a
point-to-point transmission by a one device to a single other
device.
[0073] In an example of cellular communication over a cellular
carrier via a Uu interface, for a DL transmission, the scheduling
entity (e.g., a base station) may allocate one or more REs 306
(e.g., within the control region 312) to carry DL control
information including one or more DL control channels, such as a
physical downlink control channel (PDCCH), to one or more scheduled
entities (e.g., UEs). The PDCCH carries downlink control
information (DCI) including but not limited to power control
commands (e.g., one or more open loop power control parameters
and/or one or more closed loop power control parameters),
scheduling information, a grant, and/or an assignment of REs for DL
and UL transmissions. The PDCCH may further carry hybrid automatic
repeat request (HARQ) feedback transmissions such as an
acknowledgment (ACK) or negative acknowledgment (NACK). HARQ is a
technique well-known to those of ordinary skill in the art, wherein
the integrity of packet transmissions may be checked at the
receiving side for accuracy, e.g., utilizing any suitable integrity
checking mechanism, such as a checksum or a cyclic redundancy check
(CRC). If the integrity of the transmission is confirmed, an ACK
may be transmitted, whereas if not confirmed, a NACK may be
transmitted. In response to a NACK, the transmitting device may
send a HARQ retransmission, which may implement chase combining,
incremental redundancy, etc.
[0074] The base station may further allocate one or more REs 306
(e.g., in the control region 312 or the data region 314) to carry
other DL signals, such as a demodulation reference signal (DMRS); a
phase-tracking reference signal (PT-RS); a channel state
information (CSI) reference signal (CSI-RS); and a synchronization
signal block (SSB). SSBs may be broadcast at regular intervals
based on a periodicity (e.g., 5, 10, 20, 30, 80, or 130 ms). An SSB
includes a primary synchronization signal (PSS), a secondary
synchronization signal (SSS), and a physical broadcast control
channel (PBCH). A UE may utilize the PSS and SSS to achieve radio
frame, subframe, slot, and symbol synchronization in the time
domain, identify the center of the channel (system) bandwidth in
the frequency domain, and identify the physical cell identity (PCI)
of the cell.
[0075] The PBCH in the SSB may further include a master information
block (MIB) that includes various system information, along with
parameters for decoding a system information block (SIB). The SIB
may be, for example, a SystemInformationType 1 (SIB1) that may
include various additional system information. The MIB and SIB1
together provide the minimum system information (SI) for initial
access. Examples of system information transmitted in the MIB may
include, but are not limited to, a subcarrier spacing (e.g.,
default downlink numerology), system frame number, a configuration
of a PDCCH control resource set (CORESET) (e.g., PDCCH CORESET0), a
cell barred indicator, a cell reselection indicator, a raster
offset, and a search space for SIB1. Examples of remaining minimum
system information (RMSI) transmitted in the SIB1 may include, but
are not limited to, a random access search space, a paging search
space, downlink configuration information, and uplink configuration
information. A base station may transmit other system information
(OSI) as well.
[0076] In an UL transmission, the scheduled entity (e.g., UE) may
utilize one or more REs 306 to carry UL control information (UCI)
including one or more UL control channels, such as a physical
uplink control channel (PUCCH), to the scheduling entity. UCI may
include a variety of packet types and categories, including pilots,
reference signals, and information configured to enable or assist
in decoding uplink data transmissions. Examples of uplink reference
signals may include a sounding reference signal (SRS) and an uplink
DMRS. In some examples, the UCI may include a scheduling request
(SR), i.e., request for the scheduling entity to schedule uplink
transmissions. Here, in response to the SR transmitted on the UCI,
the scheduling entity may transmit downlink control information
(DCI) that may schedule resources for uplink packet transmissions.
UCI may also include HARQ feedback, channel state feedback (CSF),
such as a CSI report, or any other suitable UCI.
[0077] In addition to control information, one or more REs 306
(e.g., within the data region 314) may be allocated for data. Such
data may be carried on one or more traffic channels, such as, for a
DL transmission, a physical downlink shared channel (PDSCH); or for
an UL transmission, a physical uplink shared channel (PUSCH). In
some examples, one or more REs 306 within the data region 314 may
be configured to carry other signals, such as one or more SIBs and
DMRSs.
[0078] In an example of sidelink communication over a sidelink
carrier via a proximity service (ProSe) PC5 interface, the control
region 312 of the slot 310 may include a physical sidelink control
channel (PSCCH) including sidelink control information (SCI)
transmitted by an initiating (transmitting) sidelink device (e.g.,
Tx V2X device or other Tx UE) towards a set of one or more other
receiving sidelink devices (e.g., Rx V2X device or other Rx UE).
The data region 314 of the slot 310 may include a physical sidelink
shared channel (PSSCH) including sidelink data transmitted by the
initiating (transmitting) sidelink device within resources reserved
over the sidelink carrier by the transmitting sidelink device via
the SCI. Other information may further be transmitted over various
REs 306 within slot 310. For example, HARQ feedback information may
be transmitted in a physical sidelink feedback channel (PSFCH)
within the slot 310 from the receiving sidelink device to the
transmitting sidelink device. In addition, one or more reference
signals, such as a sidelink SSB, a sidelink CSI-RS, a sidelink SRS,
and/or a sidelink positioning reference signal (PRS) may be
transmitted within the slot 310.
[0079] These physical channels described above are generally
multiplexed and mapped to transport channels for handling at the
medium access control (MAC) layer. Transport channels carry blocks
of information called transport blocks (TB). The transport block
size (TBS), which may correspond to a number of bits of
information, may be a controlled parameter, based on the modulation
and coding scheme (MCS) and the number of RBs in a given
transmission.
[0080] The channels or carriers illustrated in FIGS. 1, 2, and 3
are not necessarily all of the channels or carriers that may be
utilized between devices, and those of ordinary skill in the art
will recognize that other channels or carriers may be utilized in
addition to those illustrated, such as other traffic, control, and
feedback channels.
[0081] Long term evolution (LTE) and 5G new radio (5G NR) provide
greater bandwidth, both in the uplink and downlink, compared to
previous generations of cellular networks. In 5G NR networks, the
increased bandwidth is attributable to both the addition of FR2, as
well as increasing the available channel bandwidth to 100 MHz in
FRE The preceding recitation of a network and frequency ranges are
provided for illustrative and non-limiting purposes. Aspects
described herein may be appliable to other networks and other
frequency ranges, and the present application is not limited to any
particular network configuration or frequency range.
[0082] The additional bandwidth available in 5G NR may be partially
exploited by using longer orthogonal frequency-division multiplexed
(OFDM) symbols. However, longer OFDM symbols may detrimentally
increase the peak-to-average power (PAPR) for a given OFDM
transmitted signal. Clipping and filtering (CF) is a common way to
reduce PAPR in the industry. However, CF may result in in-band
distortion and may not converge to a desirable solution. In various
aspects of the disclosure, the PAPR increase resulting from the use
of longer OFDM symbols may be offset by a PAPR reduction technique
that may be referred to herein as tone reservation. As used herein,
a single tone may correspond to a single subcarrier and the terms
tone and subcarrier may be used interchangeably.
[0083] An OFDM signal may be transmitted on a set of resources. The
set of resources includes a plurality of tones. A base station may
reserve one set of resources for a downlink transmission and may
transmit an assignment of the set of resources to a UE in downlink
control information (DCI). The base station may grant another set
of resources to the UE to use for an uplink transmission. The CF
and tone reservation techniques exemplified herein may be
applicable to both downlink and uplink transmission. For ease of
reference, the set of resources used for transmission, whether
assigned or granted, will be interchangeably referred to throughout
as a set of resources, a set of resources having a plurality of
tones, or a set of granted resources having a plurality of
tones.
[0084] The tone reservation techniques exemplified herein may allow
a transmitter to transmit a desired OFDM signal on a first subset
of a plurality of tones in a set of resources. The first subset of
the plurality of tones may be referred to as data tones
irrespective of whether the first subset of the plurality of tones
carries control or traffic. The tone reservation techniques
exemplified herein may allow the transmitter to simultaneously
transmit peak reduction tones (PRTs) on a second subset of the
plurality of tones in the set of resources. The second subset of
the plurality of tones may be reserved for the purpose of PAPR
reduction. The second subset of the plurality of tones is different
from the first subset of the plurality of tones. The second subset
of the plurality of tones may be referred to as idle tones or PRTs.
The second subset of the plurality of tones may be tones that are
not used for communication (i.e., they do not carry data per se).
To minimize the PAPR of an overall signal (i.e., of the plurality
of tones in the set of resources. or of the combination of the
first subset and the second subset of the plurality of tones), the
magnitude and phase of each PRT may be optimized for a given OFDM
symbol.
[0085] A transmitter and receiver may each be configured to be
aware of which tones are data tones (i.e., the first subset of the
plurality of tones) and which tones are PRTs (i.e., the second
subset of the plurality of tones). Given that there may be no
overlap between the data tones and PRTs, the tone reservation
techniques (using PRTs) described herein may not degrade error
vector management (EVM) at a receiver and may not adversely impact
adjacent channel leakage ratio (ACLR). EVM is a measure of
modulation accuracy, or how well a power amplifier is transmitting
information. ACLR is a ratio of the filtered mean power centered on
the assigned channel frequency to the filtered mean power centered
on an adjacent channel frequency. Degradation of EVM and adverse
impact to ACLR may be avoided at least because the receiver
(knowing which tones are PRTs) may ignore the PRTs and only decode
the data tones.
[0086] FIG. 4A is a diagram illustrating an example amplitude
modulation (AM)-to-AM conversion curve for a solid state power
amplifier (SSPA) model with p=2 (where p is a parameter used to
control the AM/AM sharpness of the saturation region) according to
some aspects of the disclosure. In FIG. 4, input power in dB is
shown on the horizontal axis, and output power in dB is shown on
the vertical axis. The gain of the SSPA may be accounted for by
adding the gain to the output power. For example, for an SSPA with
a gain of 5 dB, the range of 0 to -15 dB on the vertical axis would
shift upward by 5 dB to a range of 5 to -10 dB.
[0087] In FIG. 4A, the linear region, which is the region in which
there is a one-to-one correspondence between increases in input
power and output power, extends from about -15 dB to about -2 dB.
Between the input of -2 dB to 0 dB, the SSPA begins to enter the
saturation region. By the time the input is at about 1 dB, the SSPA
is fully saturated (corresponding to a normalized output of 0 dB).
Further increases in input power of a signal at a desired frequency
produce no increase in output power at the desired frequency. In
the example of FIG. 4A, the operating point is identified as the -1
dB point, which is the point where the gain adjusted output power
is 1 dB less than the input power. For example, for an input of -5
dB, the output corresponds to -5 dB (i.e., the output linearly
follows the input), while for an input of 0 dB, the output
corresponds to -1 dB (i.e., the output is compressed by 1 dB).
Using the example of an SSPA with a gain of 5 dB, the preceding
example indicates that for an input of -5 dBm, the output
corresponds to 0 dBm, while for an input of 0 dBm, the output
corresponds to -4 dBm (i.e., 1 dB less than the output power had
the SSPA still been operating in the linear region).
[0088] An input back-off (IBO), which may be used to avoid
non-linearity due to the peak-to-average power ratio (PAPR) of the
input signal, is depicted in the example of FIG. 4A. The IBO is
depicted as being about -7.5 dB. With an IBO of -7.5 dB, the actual
operating point (e.g., the point corresponding to an average input
power) of the SSPA is maintained in the linear region, and
excursions of output power due to the PAPR allow the output power
to increase by about 6.5 dB (not the full 7.5 dB of the IBO because
the IBO corresponds to the -1 dB output power point).
[0089] FIGS. 4B, 4C, and 4D are representations of the graph of
FIG. 4A according to some aspects of the disclosure. In FIGS. 4B,
4C, and 4D, input power (P.sub.in) in dB is shown on the horizontal
axis and output power (P.sub.out) in dB is shown on the vertical
axis. The point identified as the saturation point in FIGS. 4B, 4C,
and 4D may correspond to the ideal operating point in FIG. 4A,
which corresponds to the -1 dB point in the example of FIG. 4A.
[0090] In the example of FIG. 4B, the IBO is much greater than the
PAPR. This allows the peak excursions of the SSPA to remain in the
linear region. For example, as illustrated, the peak-to-peak
amplitude difference of the input signal is equal to the
peak-to-peak amplitude difference of the output signal. However,
this is an inefficient use of the power amplifier as much of the
power amplifier's headroom is wasted.
[0091] In the example of FIG. 4C, the IBO is equal to the PAPR.
This allows the peak excursions of the SSPA not to be compressed
(or to only be compressed by about 1 dB given the example of FIG.
4A). For example, as illustrated, the peak-to-peak amplitude
difference of the input signal is equal to the peak-to-peak
amplitude difference of the output signal. Additionally, because
the IBO is equal to the PAPR, the headroom of the power amplifier
is used efficiently.
[0092] In the example of FIG. 4D, the IBO is much less than the
PAPR. In this case, the peak excursions of the input signal are
compressed, and the SSPA is being driven into saturation during the
peak excursions. This saturation condition is illustrated in FIG.
4D, where the peaks of the input signal correspond to compressed
peaks in the output signal.
[0093] Reducing the PAPR of a signal, such as a 5G NR OFDM signal,
permits the IBO of an SSPA in a transmit chain of a 5G NR
transmitter (e.g., a transmitter of a gNB or a 5G NR UE) to have a
value that allows for non-compressed use of the SSPA's
headroom.
[0094] To achieve PAPR reduction in a transmitted OFDM signal, the
amplitude and the phase of the PRTs may be adjusted for each OFDM
symbol. In addition, the location of the PRTs (e.g., identified by
subcarrier index numbers, also referred to as tone index numbers or
PRT indices) may be configured to transmitters and receivers in
advance of their use of tone reservation techniques (using PRTs).
For example, the locations of PRTs may be specified for and
configured to each transmitter and receiver in a 5G NR system.
Additionally, to reduce computational complexity, instead of
adjusting the magnitude and phase of each PRT in real-time,
universal tone index numbers for PRTs may be employed according to
aspects described herein.
[0095] FIG. 5 is a plot of data tones and PRTs in the frequency
domain according to some aspects of the disclosure. As used herein,
the term "data" encompasses both traffic (e.g., downlink traffic
112, uplink traffic 116 of FIG. 1) and control (e.g., downlink
control 114, uplink control 118 of FIG. 1). According to aspects
herein, a plurality of PRTs in a set of resources may be fixed by
specifications or may be otherwise predetermined such that a
transmitter and a receiver are aware of which tones in the set of
resources are configured for data and which tones in the set of
resources are configured for PRTs.
[0096] In FIG. 5, frequency is represented along the horizontal
axis and amplitude is represented along the vertical axis. In the
example of FIG. 5, there are 24 tones, each corresponding to a
respective subcarrier index number 502. In the example of FIG. 5,
the 24 subcarrier index numbers 502 range from subcarrier index
number 0 to subcarrier index number 23. A signal representation, or
mask, in the frequency domain 504, with binary 1 indicating a
subcarrier used for a PRT and binary 0 indicating a subcarrier used
for data, is illustrated. Each tone corresponds to a frequency
component of one resource element (RE) 504. For a signal
representation or mask in accordance with 5G NR, one resource block
(RB) is one RE wide (e.g., one symbol) by 12 subcarriers.
Accordingly, the series of tones 500 of FIG. 5 corresponds to two
RBs (resource block 1506 and resource block 2508).
[0097] The example of FIG. 5 is provided for illustrative purposes
and is non-limiting. The illustrated amplitudes of the tones and
their relative differences are for ease of graphic representation.
The phase of each tone is not represented to avoid cluttering the
drawing. Varying amplitudes and phases and varying relative
differences between amplitudes and phases are within the scope of
this disclosure. In the example shown in FIG. 5, a wireless
communication apparatus (e.g., a scheduling entity or a scheduled
entity) may utilize two contiguous RBs including 24 contiguous
tones for a transmission; however, the use of two non-contiguous
RBs, or combinations of various interlaced resource elements
including non-contiguous or partially contiguous tones for
transmissions are within the scope of the disclosure. Furthermore,
applications of the tone reservation techniques (using PRTs)
described herein are not limited to 24 tones ranging from
subcarrier index number 0 to subcarrier index number 23. As known
to those of skill in the art, for a 100 MHz bandwidth, there are
3264 available tones. The aspects described herein may be
configured to a subset of the 3264 available tones or even all 3264
available tones.
[0098] In the examples described herein, the term "transmitter" may
refer to a scheduling entity (e.g., a base station, a gNB) that
transmits a downlink to a receiving scheduled entity (e.g., a UE)
or may refer to a scheduled entity (e.g., a UE) that transmits an
uplink to a receiving scheduling entity (e.g., a gNB). Depending on
the context, the term "transmitter" may refer to a transmitter
circuit of a given apparatus (e.g., a scheduling or scheduled
entity) or refer to the given apparatus itself. Likewise, depending
on the context, the term "receiver" may refer to a receiver circuit
of a given apparatus (e.g., a scheduling or scheduled entity) or
the apparatus itself.
[0099] According to some aspects, a sequence of tones in a given
set of resources (e.g., a set of granted resources having a
plurality of tones) may be preassigned as a PRT sequence. In some
examples, the tones of the PRT sequence may not be used for data.
However, according to some aspects, a transmitter may inform a
receiver that the transmitter is, or is not, using tone reservation
techniques (using PRTs) such as those described herein. The
receiver may be informed about whether the transmitter is, or is
not, using tone reservation techniques (using PRTs) based, for
example, on one bit conveyed in user plane data or control plane
signaling. If the transmitter is not using tone reservation
techniques (e.g., signified by the one bit representing "false"),
then a given preassigned sequence of tones is not used as PRTs and
may instead be used for data. In other words, if the transmitter is
not using tone reservation techniques (e.g., signified by the one
bit representing "false"), then all tones in a given set of
resources may be used for data and all tones may be decoded. If the
transmitter is using tone reservation techniques (e.g., signified
by the one bit representing "true"), then only a first subset of
the plurality of tones of the set of resources may be used for data
and is intended to be decoded, while a second subset of the
plurality of tones of the set of resources, different from the
first subset of the plurality of tones, may be used for PRTs and
may be ignored (e.g., may not be decoded) by the receiver.
[0100] The transmitter may base a decision to use tone reservation
techniques (using PRTs) on, for example, the availability of
resources. For example, if a transmitter has a large amount of data
in a buffer that is awaiting transmission, the transmitter may
determine not to use the tone reservation techniques and instead,
use all available resources for the transmission of the buffered
data. The transmitter may base a decision to use, or not use, tone
reservation techniques on other aspects or considerations, such as
quality of service (QoS) or latency associated with data awaiting
transmission stored in the buffer of the transmitter. Other factors
on which a transmitter may base a decision to use, or not use, tone
reservation techniques are within the scope of the disclosure.
[0101] A subset (e.g., the second subset) of the plurality of tones
in a set of resources may be pre-assigned as PRTs. The
pre-assignment may be, for example, fixed by specifications and
configured on both scheduling entities (e.g., base stations, gNBs)
and scheduled entities (e.g., UEs). In some examples, both a
scheduling entity and a scheduled entity may be pre-configured with
tone identifiers (IDs) (e.g., subcarrier index numbers 502) of each
of the tones in any given set of tones that are reserved as PRTs.
In other examples, if a scheduling entity and a scheduled entity
are not aware of a pre-assignment of PRTs or have not been
pre-configured as to the location of the PRTs, then a scheduling
entity may make the scheduled entity aware of the selection
through, for example, signaling.
[0102] In the example of FIG. 5, the short bars, represented by
subcarrier index numbers 0, 4, 5, 7, 9, 10, 11, 14, 15, 18, 20, and
21 are selected as PRTs (e.g., the second subset). The long bars,
represented by subcarrier index numbers 1, 2, 3, 6, 8, 12, 13, 16,
17, 19, 22, and 23 represent data tones (e.g., the first subset of
the plurality of tones). Together, the 24 subcarriers may
correspond to one OFDM signal that includes 24 tones.
[0103] To transform from the frequency domain of FIG. 5 to the time
domain, the UE may take an inverse fast Fourier transform (IFFT) of
the OFDM signal of FIG. 5.
[0104] In addition, a signal-to-clipping noise-ratio-tone
reservation (SCR-TR) technique may be used to optimize the
amplitude and phase of the PRTs (e.g., the second subset of the
plurality of tones) when given the location of the reserved tones
(e.g., when the index numbers of the PRTs are known).
[0105] According to aspects described herein, a set of resources
may be expressed as a set {1, . . . , N} (in the example of FIG. 5
{0, . . . , 23}) of tones. Let .PHI. be a subset of the set {1, . .
. , N} corresponding to the locations of the PRTs (in the example
of FIG. 5, ={0, 4, 5, 7, 9, 10, 11, 14, 15, 18, 20, 21}). The
subset .PHI. may be referred to as the second subset herein. The
remaining subset of tones {1, 2, 3, 6, 8, 12, 13, 16, 17, 19, 22,
and 23} may be used for data tones and may be referred to as the
first subset herein. The first subset of tones may be identified as
{1, . . . , N}\ .PHI., where the "\" in the formula A\B is known as
a relative complement, and the formula in the form of A\B indicates
"the objects that belong to A and not to B." Therefore, {1, . . . ,
N}\ .PHI.={1, 2, 3, 4, 6, 8, 12, 13, 16, 17, 19, 22, 23} in the
example of FIG. 5.
[0106] According to SCR-TR, a frequency domain kernel, P.sub.1, may
be constructed, where:
P i = { 1 if .times. .times. i .di-elect cons. .PHI. 0 if .times.
.times. i .di-elect cons. [ N ] .times. \ .times. .PHI. ( 1 )
##EQU00001##
where i is an index number of a tone (e.g., i=subcarrier index
number) and [N] represents {1, . . . , N}. Therefore, the formula
in the form of i.di-elect cons..PHI. indicates "i is an element of
.PHI." and the formula in the form of i.di-elect cons.[N]\.PHI.
indicates "i is not an element of .PHI.."
[0107] Next, a time domain representation, p, of the frequency
domain kernel, P, is obtained by taking the inverse fast Fourier
transform of P, where:
p=ifft(P) (2)
[0108] Next, let X be the frequency domain data that is represented
in the illustration of FIG. 5 by long vertical bars (i.e., the
subcarriers corresponding to the first subset of the plurality of
tones). It may be observed that X.sub.i=0, if i.di-elect
cons..PHI.. In other words, the data of the ith value of X
(X.sub.i) is equal to 0 if i is an element of .PHI. (i.e., if i is
an element of the set of subcarrier index numbers allotted to the
second subset of the plurality of tones). According to SCR-TR, a
frequency domain kernel, X.sub.1, may be constructed, where:
X i = { 1 if .times. .times. i .di-elect cons. .PHI. 0 if .times.
.times. i .di-elect cons. [ N ] .times. \ .times. .PHI. ( 3 )
##EQU00002##
[0109] Next, a time domain representation, x, of the frequency
domain kernel, X, is obtained by taking the inverse fast Fourier
transform of X, where:
x=ifft(X) (4)
[0110] Two observations may be made with respect to the SCR-TR
algorithm for tone reservation. First, the time domain kernel p
looks like a delta function with negligible side-lobes if the
number of reserved tones is sufficiently large and the locations
are appropriately chosen. For example, the time domain kernel p may
be represented by a single prominent main lobe peak and sidelobes
with relatively much less amplitude than the main lobe. The
waveform p 606 of FIG. 6 (i.e., the waveform represented in
dashed-line form) exemplifies these characteristics. Second,
circularly shifting p in the time domain does not impact the
location of reserved tones in the frequency domain, but rather
disturbs their phase. The indices corresponding to the value 0 in
Equation 1 (which correspond to the data tones) may not be changed
by the process of shifting p in the time domain. Therefore, in the
frequency domain, the desired signal X is unchanged by the PRT
technique described herein.
[0111] Thus, the SCR-TR algorithm for tone reservation may include
the following four steps: [0112] 1. Find the location of the
largest peak of x. Let j.di-elect cons.{1, . . . , N} be the index,
where N is an integer. [0113] 2. Circularly shift p so that the
peaks are aligned. For example, p.sub.j=circshift(p, j), where
circshift (p, j) is the circular shift of p by j units to the
right. The value of j may be incremented to produce the circular
shift of the original waveform p. For example, in FIG. 6, if the
presently used index j is 3, then p 606 would be the original
waveform shifted to the right by 3 units. [0114] 3. Subtract a
scaled and shifted p from x to obtain
[0114] x new = x - x .function. ( j ) - .mu. p .function. ( 0 )
.times. p j .times. e i .circleincircle. x .function. ( j ) ,
##EQU00003##
where .mu. is the target peak, <x(j) is the phase of x(j), i=
{square root over (-1)}, the scaling term is
x .function. ( j ) - .mu. p .function. ( 0 ) ##EQU00004##
and the scaling term may be changed for each peak, and represents
the phase shift of p.sub.i and the phase shift may be changed for
each peak [0115] 4. Iterate several times to reduce several
peaks.
[0116] FIG. 6 is a plot 600 of a data tones 602 and PRTs 606 in the
time domain according to some aspects of the disclosure. The plot
600 may be used to explain steps 1 and 2 of the above-described
SCR-TR algorithm for tone reservation, for example. In FIG. 6, time
is represented along the horizontal axis and amplitude is
represented along the vertical axis. The multi-peaked waveform
corresponds to x 602 (shown in solid line), which is the time
domain representation of the frequency data (i.e., the first subset
of the plurality of tones). The largest peak 604 of x 602 appears
in the middle of the illustration. The largest peak 604 may be
referred to as a target peak. The singularly peaked waveform
corresponds to p 606 (shown in dashed line), which is the time
domain representation of the peak reduction tones (PRTs) (i.e., the
second subset of the plurality of tones). In the illustration of
FIG. 6, p 606 has been circularly shifted (e.g., moved from
left-to-right or right-to-left) and scaled in amplitude so that the
largest peak 604 of x 602 (e.g., the target peak of x) and the peak
of p 606 are aligned. The circular shift may be graphically
represented by the double-headed arrow 608. In the next step, step
3, the scaled and shifted p is subtracted from x to obtain a new x,
referred to as x.sub.new, and steps 1-3 are repeated to reduce the
peaks of x.sub.new. In this manner, the PAPR of x may be
reduced.
[0117] FIGS. 7A, 7B, and 7C are diagrams illustrating example time
domain representations of various inverse fast Fourier transforms
(IFFTs) of respective sets of reserved tones according to some
aspects of the disclosure. In FIGS., 7A, 7B, and 7C, time is
represented on the horizontal axis while amplitude is represented
on the vertical axis. In FIG. 7A, a single relatively wide lobe 702
is produced from an IFFT of a set of contiguous tones in the
frequency domain. In comparison to the time domain kernel p of FIG.
6, the single relatively wide lobe 702 of FIG. 7A may be inferior
for the purposes of the SCR-TR algorithm described above. In FIG.
7B, a uniform comb 704 in the time domain is produced. In
comparison to the time domain kernel p of FIG. 6, the width of a
primary lobe (in the center of the image) is narrow; however, the
side lobes (i.e., the high peak signals to the left and right of
the center lobe) have amplitudes that are substantially similar to
that of the main lobe. This plurality of equally spaced lobes may
make this waveform unsuitable for step 3 of the SCR-TR algorithm.
In FIG. 7C, a single narrow main lobe 706 in the time domain is
flanked on either side by smaller sidelobes 708. The waveform of
FIG. 7C may be produced by taking an IFFT of a random set of
subcarriers in the frequency domain. FIG. 7C may represent a
reasonable trade-off between the wide main lobe of FIG. 7A and the
comb of narrow lobes in FIG. 7B.
[0118] A perfect kernel may be desirable to implement the PRT
techniques described herein. For example, for a sequence A.sub.0, .
. . , A.sub.n-1, with A.sub.i.di-elect cons.{0,1}, one can define a
modular autocorrelation as:
B.sub.j=.SIGMA..sub.i=0.sup.n-1A.sub.iA.sub.mod(i+j,n),for j=0, . .
. ,n-1 (5)
[0119] The modular autocorrelation may be considered perfect if
B.sub.1=constant, for j.noteq.0.
[0120] A sequence A.sub.0, . . . , A.sub.n-1 (in the frequency
domain) with perfect autocorrelation, generates a perfect kernel,
a, where a=ifft(A). For the perfect kernel:
B j = { c , for .times. .times. j = 0 d , for .times. .times. j
.noteq. 0 [ ifft .function. ( B ) ] j = b = { c + d * ( n - 1 ) ,
for .times. .times. j = 0 c - d , for .times. .times. j .noteq. 0 (
6 ) .times. a = ifft .function. ( A ) = ifft .function. ( B ) ( 7 )
##EQU00005##
[0121] FIG. 8 depicts an imperfect kernel 802 and a perfect kernel
804 according to some aspects of the disclosure. For the perfect
kernel 804, in the time domain of FIG. 8, b=c+d*(n-1) 806 for the
main lobe (j=0) and b=c-d everywhere else (j.noteq.0). Accordingly,
b is referred to as a perfect kernel.
[0122] To find which sequences generate perfect autocorrelation,
one may consider a sequence A.sub.0, . . . , A.sub.n-1 with A.sub.i
E OM. Let S{0, . . . , n-1} represent the non-zero indices of a.
The nomenclature S{0, . . . , n-1} means that S is a subset of the
set {0, . . . , n-1}. The autocorrelation can be alternatively
given as:
B.sub.j=.SIGMA..sub.i=0.sup.n-11.sub.{{i,mod(i+j,n)}S} for j=0, . .
. ,n-1 (8)
or
B.sub.j=.SIGMA..sub.{i,k}S1.sub.{mod(k-i,n)=j} for j=0, . . . ,n-1
(9) [0123] where 1.sub.p corresponds to an indicator function
defined on a logical statement p having the value of 1 when p is a
true statement and having the value 0 when p is a false
statement.
[0124] For a given series A.sub.0, . . . , A.sub.n-1 with a
corresponding set S, the autocorrelation B is perfect if every
j.di-elect cons.{1, . . . , n-1} can be written in exactly ways as
a difference of elements of S, where .lamda. is independent of
j.
[0125] Such a set S may be referred to herein as a "difference set"
with repetition .lamda.. According to some aspects, the number of
peak reduction tones squared may be approximately equal to the
total number of tones multiplied by 2, as mathematically expressed
below:
numPRT.sup.2.apprxeq.numTones.times..lamda. (10)
[0126] A perfect ruler is a set of integers S{0, . . . , n-1}
constructed such that the pairwise differences of the elements of S
modulus n form a closed interval of integers. A perfect ruler
corresponds to a difference set with .lamda.=1 (each difference is
repeated only once).
[0127] By way of example, using S as PRT indices results in a
perfect kernel. For instance, consider:
S={0,1,5} {0,1, . . . ,6} (11)
[0128] The difference set (e.g., the pairwise differences between
the pairs 0 and 1, 1 and 5, and 5 and 0) of S is given by:
{1-0,5-0,0-1,0-5,1-5,5-1} mod 7 (12)
which is equal to {1,5,6,2,3,4} (13)
A determination may be made as to whether the set S is a difference
set based on the set given in Equation 13. For example, the set
given in Equation 13 may be sorted to determine if that set forms a
contiguous interval. Here {1, 2, 3, 4, 5, 6} forms a contiguous
interval (all the members of the interval are covered).
Furthermore, each element is repeated exactly once. Consequently,
the set S of Equation 13 is a difference set.
[0129] As to PRTs, for the example set S={0, 1, 5}, the frequency
domain representation may be given by A, where:
A=[1 1 0 0 0 1 0] (14)
The values of the matrix A are realized by recognizing that the
0.sup.th value of the nine values in A is set to 1, the 1.sup.st
value of the nine values is set to 1, and the 5.sup.th value of the
nine values is set to 1; this corresponds to the set S={0, 1, 5}.
Next, the autocorrelation of A is determined:
A* =[3 1 1 1 1 1 1] (15)
The observation may be that when a contiguous interval exists (as
in Equation 13), there will be a perfect autocorrelation, as shown
in Equation 15. The autocorrelation of A is perfect because at
index 0, the autocorrelation has one value and outside of index 0
the autocorrelation has a constant second value, namely 3 and 1,
respectively. As shown in Equation 16 below, when an inverse fast
Fourier transform is taken of the perfect autocorrelation, that
inverse fast Fourier transform is also perfect. Additionally, one
can take the square root of the inverse fast Fourier transform to
produce the kernel in the time domain, and that too is perfect as
shown in Equation 17.
ifft(A*A)=[9 2 2 2 2 2 2] (16)
{square root over (|a|)}= {square root over (|ifft(A)|)}
=[31.41.41.41.41.41.4] (17)
[0130] The above description considers a perfect ruler. In other
examples, instead of a perfect ruler, a Golomb ruler may be used.
In mathematics, a Golomb ruler is a set of marks at integer
positions along an imaginary ruler such that no two pairs of marks
are the same distance apart. The number of marks on the ruler
corresponds to the order, and the largest distance between two
marks corresponds to the length of the ruler. In other words, a
Golomb ruler is a set of integers S{0, . . . , n-1} such that the
pairwise differences of the elements of S modulus n are
distinct.
[0131] A Golomb ruler that is able to measure all distances up to
its length may be referred to as a perfect Golomb ruler. No perfect
Golomb ruler exists for five or more marks. A Golomb ruler may be
referred to as an optimal Golomb ruler if no shorter Golomb ruler
of the same order exists. An optimal (maximally dense) Golomb ruler
maximizes |S| for a given n. For specific choices of n, an optimal
Golomb ruler may result in a sequence with perfect autocorrelation,
which in turn results in a perfect kernel.
[0132] Generating an optimal Golomb ruler may be considered to be
non-deterministic polynomial-time (NP) hard (NP-hard). In
computational complexity theory, NP-hardness is the defining
property of a class of problems that are informally at least as
hard as the hardest problems in NP. However, there are efficient
constructions for near-optimal Golomb rulers, such as the Ruzsa
construction:
S=q*(1:q-1)+(q-1)*g.sup.1:(q-1 mod q(q-1), (18)
where q is a prime and g is a primitive root of .sub.q.
[0133] Given the Ruzsa construction of Equation 18, the absolute
value of the set of integers S may be given as:
|S|=q-1 and n=q(q-1) (19)
[0134] As used herein, the term Golomb ruler refers to an optimal
Golomb ruler, as defined herein. As shown in Table I below, there
are currently 27 known optimal Golomb rulers.
TABLE-US-00001 TABLE I Known Optimal Golomb Rulers Order (x) Marks
1 0 2 0 1 3 0 1 3 4 0 1 4 6 5 0 1 4 9 11 6 0 1 4 10 12 17 7 0 1 4
10 18 23 25 8 0 1 4 9 15 22 32 34 9 0 1 5 12 25 27 35 41 44 10 0 1
6 10 23 26 34 41 53 55 11 0 1 4 13 28 33 47 54 64 70 72 12 0 2 6 24
29 40 43 55 68 75 76 85 13 0 2 5 25 37 43 59 70 85 89 98 99 106 14
0 4 6 20 35 52 59 77 78 86 89 99 122 127 15 0 4 20 30 57 59 62 76
100 111 123 136 144 145 151 16 0 1 4 11 26 32 56 68 76 115 117 134
150 163 168 177 17 0 5 7 17 52 56 67 80 81 100 122 138 159 165 168
191 199 18 0 2 10 22 53 56 82 83 89 98 130 148 153 167 188 192 205
216 19 0 1 6 25 32 72 100 108 120 130 153 169 187 190 204 231 233
242 246 20 0 1 8 11 68 77 94 116 121 156 158 179 194 208 212 228
240 253 259 283 21 0 2 24 56 77 82 83 95 129 144 179 186 195 255
265 285 293 296 310 329 333 22 0 1 9 14 43 70 106 122 124 128 159
179 204 223 253 263 270 291 330 341 353 356 23 0 3 7 17 61 66 91 99
114 159 171 199 200 226 235 246 277 316 329 348 350 366 372 24 0 9
33 37 38 97 122 129 140 142 152 191 205 208 252 278 286 326 332 353
368 384 403 425 25 0 12 29 39 72 91 146 157 160 161 166 191 207 214
258 290 316 354 372 394 396 431 459 467 480 26 0 1 33 83 104 110
124 163 185 200 203 249 251 258 314 318 343 356 386 430 440 456 464
475 487 492 27 0 3 15 41 66 95 97 106 142 152 220 221 225 242 295
330 338 354 382 388 402 415 486 504 523 546 553
[0135] FIG. 9 is a diagram of an example representation of an RF
signal 900 in the frequency domain including 31 tones
(subcarriers), where 25 of the tones are data tones (e.g., the
first subset of the plurality of tones) and 6 of the tones are peak
reduction tones (PRTs) (e.g., the second subset of the plurality of
tones) according to some aspects of the disclosure. The subcarrier
index numbers 902 running from index value 0 to index value 30 are
identified. The signal representation, or mask, in the frequency
domain 904, with binary 1 indicating a subcarrier used for a PRT
and binary 0 indicating a subcarrier used for data, is illustrated.
The RF signal of FIG. 9 may be used in the calculation of the
complementary cumulative distribution function (CCDF) of PAPR per
symbol, illustrated in FIG. 10A and the CCDF of PAPR per tone
illustrated in FIG. 10B.
[0136] FIG. 10A is a diagram illustrating the cumulative
distribution function (CCDF) of peak-to-average power ratio (PAPR)
per symbol for the RF signal of 31 tones illustrated in FIG. 9
according to some aspects of the disclosure. FIG. 10B is a diagram
illustrating the CCDF of PAPR per tone for the same RF signal of 31
tones illustrated in FIG. 9 according to some aspects of the
disclosure. The CCDF curves of FIGS. 10A and 10B show the
probability that the instantaneous signal power will be higher than
the average signal power by a certain amount of dB. As described in
connection with FIG. 9, the RF signal includes 31 tones
(subcarriers), where 25 of the tones are data tones, and 6 of the
tones are peak reduction tones (PRTs). In FIGS. 10A and 10B, the
measure of the ratio of instantaneous signal power to average
signal power in dB is provided on the horizontal axis, while the
CCDF of PAPR per symbol and CCDF of the PAPR per tone are provided
on the vertical axis.
[0137] Turning to FIG. 10A, the CCDF of the peak-to-average power
ratio (PAPR) in dB is highest if no PRT 1002 technique is used to
reduce the PAPR, lowest if an optimal Golomb ruler 1004 is used to
implement the PRT technique to reduce the PAPR, and somewhere
between the no PRT 1002 case and the optimal Golomb ruler 1004 case
if random PRTs 1006 are used to implement the PRT technique to
reduce the PAPR.
[0138] Turning to FIG. 10B, the CCDF of the peak-to-average power
ratio (PAPR) in dB is highest if no PRT 1008 technique is used to
reduce the PAPR, lowest if an optimal Golomb ruler 1010 is used to
implement the PRT technique to reduce the PAPR, and somewhere
between the no PRT 1008 case and the optimal Golomb ruler 1010 case
if random PRTs 1012 are used to implement the PRT technique to
reduce the PAPR.
[0139] As explained above and illustrated in Table I, the highest
order of known optimal Golomb rulers is 27 (i.e., x=27). As used
herein, the value of the order corresponds to the number of peak
reduction tones (PRTs). Given that an optimal Golomb ruler of order
x is suitable for reducing the PAPR of a signal of
length.apprxeq.x.sup.2 tones, the optimal Golomb ruler of order 27
will support up to 27.sup.2 tones; that is, 27*27=729 tones, or
729/12.apprxeq.60 RBs (given that there are 12 tones per RB). Here,
the 729 tones refer to the total number of tones (e.g., the data
tones plus the PRTs) of an RF signal. A transmitter may utilize
more than 60 RBs. For example, for a channel that has a 100 MHz
bandwidth, a transmitter may utilize up to 273 RBs (corresponding
to 3276 tones).
[0140] If a transmitter utilizes 60 RBs or less, the following
process may be used to construct the PRT sequence used by the
transmitter: [0141] 1. Let x represent the square root of the
number of tones in the set of resources utilized by the
transmitter, rounded up to a closest positive integer (e.g., the
transmitter utilizes a plurality of about x.sup.2 tones, where
there are 12 tones per RB). [0142] 2. Select from Table I, above, a
Golomb ruler of order x. The marks on the Golomb ruler represent
peak reduction tone indices. [0143] 3. Construct the PRT sequence,
r, as a sequence of zeros and ones of a quantity equal to the
number of tones utilized by the transmitter. The value of the
sequence is equal to 1 at the selected peak reduction tone indices
and zero otherwise. It should be understood that the use of the
binary 1 at the selected peak tone indices and zero otherwise is
only exemplary. It is within the scope of the disclosure to use the
binary 0 at the selected peak tone indices and 1 otherwise.
[0144] The PRT sequence r, constructed in the example above and in
the examples that follow, may be interpreted in the frequency
domain. PRT sequence r may be similar to the frequency domain
kernel, P (of Equation 1). It is zero at the data tones and 1 at
the peak reduction tones.
[0145] If a transmitter utilizes between 60 RBs and 120 RBs, the
following process may be used: [0146] 1. Obtain a set of marks of a
Golomb ruler corresponding to half the number of utilized RBs.
Obtaining the set of marks of the Golomb ruler for half the number
of utilized RBs reduces the number of resource blocks to at most 60
RBs, which is within the computational limits of 729 tones or 60
RBs identified above. [0147] 2. Let an initial PRT sequence (in the
time domain) corresponding to this Golomb ruler be r. [0148] 3.
Uniformly interleave r with one copy of itself to construct (or
obtain) the PRT sequence corresponding to the full number of
utilized RBs.
[0149] This can be equivalently represented as:
PRTseq .function. ( i ) = { r .function. ( i 2 ) .times. .times. if
.times. .times. mod .function. ( i , 2 ) = 0 r .function. ( i - 1 2
) .times. .times. if .times. .times. mod .function. ( i , 2 ) = 1 (
20 ) ##EQU00006##
where i is the index number of a tone (e.g., i=subcarrier index
number), and the nomenclature mod(i, 2) means "i mod 2."
[0150] One half of 60 to 120 RBs corresponds to 30 to 60 RBs,
respectively. With 12 tones per RB, this corresponds to 360 to 720
tones, respectively. The square roots of 360 to 720 tones rounded
up to the closest positive integer correspond to 19 to 27 tones,
respectively, which correspond to Golomb rulers of order 19 to 27,
respectively. Providing an example using Golomb rulers having these
large orders would be unwieldy. To provide a more easily understood
example, suppose the total number of RBs was 1.5 RBs. Half of 1.5
RBs corresponds to 0.75 RBs, which corresponds to 9 tones (i.e.,
x.sup.2=9). The Golomb ruler order is given by the square root of
the total number of tunes (i.e., order=x= {square root over
(9)}=3). From Table I, the Golomb ruler corresponding to the order
of 3 is {0,1,3} in the frequency domain. Given that the marks of
the Golomb ruler are {0,1,3}, an initial PRT sequence of length 9
(corresponding to the 9 tones) in the time domain may be expressed
as r=[1 1 0 1 0 0 0 0 0]. Notice that the marks having the binary
value of 1 correspond to "indices" 0, 1, and 3. In this PRT
sequence, indices 0, 1, and 3 are set to a binary value of 1 while
the remaining indices (2, 4, 5, 6, 7, and 8), corresponding to
data, are set to 0. That is, the 0.sup.th tone of the nine tones is
set to 1, the 1.sup.st tone of the nine tones is set to 1, and the
3.sup.rd tone of the nine tones is set to 1 (corresponding to the
Golomb ruler of {0,1,3}), while the remaining tones of the set are
set to 0. The total number of RBs (i.e., 2*0.75 RBs=1.5 RBs)
corresponds to 18 tones (i.e., 2*0.75 RBs=1.5 RBs=18 tones) in the
time domain.
[0151] To obtain the entire PRT sequence for 18 tones, the
transmitter may uniformly interleave r ([1 1 0 1 0 0 0 0 0]) with
one copy of itself ([1 1 0 1 0 0 0 0 0]), which yields: r=[1 1 1 1
0 0 1 1 0 0 0 0 0 0 0 0 0 0], where italics are used only to
highlight the interleaving of r with the copy of itself. The same
PRT sequence may be constructed using Equation 20. In the example,
i, which is an index that spans the total number of tones, is 18
(corresponding to subcarrier index numbers i of 0-17). For i=0, 0
mod 2=0, so the PRTseq for the 0.sup.th element would be
r(0/2)=r(0)=1. For i=1, 1 mod 2=1, so the PRTseq for the 1.sup.st
element would be r(1-1/2)=r(0)=1. For i=2, 2 mod 2=0, so the PRTseq
for the 2.sup.nd element would be r(2/2)=r(1)=1. For i=3, 3 mod
2=1, so the PRTseq for the 3rd element would be
r .function. ( 3 - 1 2 ) = r .function. ( 2 / 2 ) = r .function. (
1 ) = 1. ##EQU00007##
For i=4, 4 mod 2=0, so the PRTseq for the 4th element would be
r(4/2)=r(2)=0. For i=5, 5 mod 2=1, so the PRTseq for the 5th
element would be
r .function. ( 5 - 1 2 ) = r .function. ( 4 / 2 ) = r .function. (
2 ) = 0. ##EQU00008##
For i=6, 6 mod 2=0, so the PRTseq for the 6th element would be
r(6/2)=r(3)=1. For i=7, 7 mod 2=1, so the PRTseq for the 7th
element would be
r .function. ( 7 - 1 2 ) = r .function. ( 3 ) = 1. ##EQU00009##
For i=8, 8 mod 2=0, so the PRTseq for the 8th element would be
r(8/2)=r(4)=0. For i=9, 9 mod 2=1, so the PRTseq for the 9th
element would be
r .function. ( 9 - 1 2 ) = r .function. ( 8 / 2 ) = r .function. (
4 ) = 0 .times. .times. ##EQU00010##
and so on. The sequence may continue to be constructed in this
manner.
[0152] If a transmitter utilizes between 120 RBs and 180 RBs, the
following process may be used: [0153] 1. Obtain a set of marks of a
Golomb ruler corresponding to one third of the number of utilized
RBs. Obtaining the set of marks of the Golomb ruler for one third
of the number of utilized RBs reduces the number of resource blocks
to at most 60 RBs, which is within the computational limits of 729
tones or 60 RBs identified above. [0154] 2. Let an initial PRT
sequence corresponding to this Golomb ruler be r. [0155] 3.
Uniformly interleave r with two copies of itself to construct (or
obtain) the PRT sequence corresponding to the number of utilized
RBs.
[0156] This can be equivalently represented as:
PRTseq .function. ( i ) = { r .function. ( i 3 ) .times. .times. if
.times. .times. mod .function. ( i , 3 ) = 0 r .function. ( i - 1 3
) .times. .times. if .times. .times. mod .function. ( i , 3 ) = 1 r
.function. ( i - 2 3 ) .times. .times. if .times. .times. mod
.function. ( i , 3 ) = 2 ( 21 ) ##EQU00011##
[0157] If a transmitter utilizes between 180 RBs and 240 RBs, the
following process may be used: [0158] 1. Obtain a set of marks of a
Golomb ruler corresponding to one fourth of the number of utilized
RBs. Obtaining the set of marks of the Golomb ruler for one fourth
of the number of utilized RBs reduces the number of resource blocks
to at most 60 RBs, which is within the computational limits of 729
tones or 60 RBs identified above. [0159] 2. Let an initial PRT
sequence corresponding to this ruler be r. [0160] 3. Uniformly
interleave r with three copies of itself to construct (or obtain)
the PRT sequence corresponding to the number of utilized RBs.
[0161] This can be equivalently represented as:
PRTseq .function. ( i ) = { r .function. ( i 4 ) .times. .times. if
.times. .times. mod .function. ( i , 4 ) = 0 r .function. ( i - 1 4
) .times. .times. if .times. .times. mod .function. ( i , 4 ) = 1 r
.function. ( i - 2 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 2 r .function. ( i - 3 4 ) .times. .times.
if .times. .times. mod .function. ( i , 4 ) = 3 ( 22 )
##EQU00012##
[0162] If a transmitter utilizes between 240 RBs and 300 RBs, the
following process may be used: [0163] 1. Obtain a set of marks of a
Golomb ruler corresponding to one fifth of the number of utilized
RBs. Obtaining the set of marks of the Golomb ruler for one fifth
of the number of utilized RBs reduces the number of resource blocks
to at most 60 RBs, which is within the computational limits of 729
tones or 60 RBs identified above. [0164] 2. Let an initial PRT
sequence corresponding to this ruler be r. [0165] 3. Uniformly
interleave r with four copies of itself to construct (or obtain)
the PRT sequence corresponding to the number of utilized RBs.
[0166] This can be equivalently represented as:
PRTseq .function. ( i ) = { r .function. ( i 5 ) .times. .times. if
.times. .times. mod .function. ( i , 5 ) = 0 r .function. ( i - 1 5
) .times. .times. if .times. .times. mod .function. ( i , 5 ) = 1 r
.function. ( i - 2 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 2 r .function. ( i - 3 5 ) .times. .times.
if .times. .times. mod .function. ( i , 5 ) = 3 r .function. ( i -
4 5 ) .times. .times. if .times. .times. mod .function. ( i , 5 ) =
4 ( 23 ) ##EQU00013##
[0167] Employing the PRT techniques described herein may lower the
PAPR without requiring a transmitter to optimize the location of
PRTs. Optimization of location may not be required because,
according to aspects described herein, for a given set of
resources, the location of the PRTs (e.g., the PRT sequence) is
known in advance to both the transmitter and a receiver. According
to some aspects, the location of the PRTs in any given set of
resources may be predetermined and fixed in a specification that
covers, for example, the use of uplink and downlink resources for
scheduled entities and scheduling entities. Furthermore, the PRT
techniques described herein may avoid implementation of a new
channel for informing the receiver of the location (e.g., the PRT
sequence) of tones selected for use as PRTs, because the
transmitter and receiver both know in advance for any given set of
resources, the PRT sequence that identifies tones used as PRTs.
[0168] FIG. 11 is a block diagram illustrating an example of a
hardware implementation for a wireless communication apparatus 1100
employing a processing system 1102 according to some aspects of the
disclosure. The wireless communication apparatus 1100 may be, for
example, a scheduling entity, which may be exemplified as a base
station, an eNB, a gNB, a network access node as illustrated in any
one or more of FIGS. 1 and/or 2. Alternatively, the wireless
communication apparatus 1100 may be, for example, a scheduled
entity, which may be exemplified as a UE or mobile communication
device as illustrated in any one or more of FIGS. 1 and/or 2.
[0169] In accordance with various aspects of the disclosure, an
element, or any portion of an element, or any combination of
elements may be implemented with a processing system 1102 that
includes one or more processors, such as processor 1104. Examples
of processors 1104 include microprocessors, microcontrollers,
digital signal processors (DSPs), field programmable gate arrays
(FPGAs), programmable logic devices (PLDs), state machines, gated
logic, discrete hardware circuits, and other suitable hardware
configured to perform the various functionality described
throughout this disclosure. In various examples, the wireless
communication apparatus 1100 may be configured to perform any one
or more of the functions described herein. That is, the processor
1104, as utilized in the wireless communication apparatus 1100, may
be used to implement any one or more of the methods or processes
described and illustrated, for example, in FIGS. 10, 11, and/or
12.
[0170] The processor 1104 may in some instances be implemented via
a baseband or modem chip and in other implementations, the
processor 1104 may include a number of devices distinct and
different from a baseband or modem chip (e.g., in such scenarios as
may work in concert to achieve examples discussed herein). And as
mentioned above, various hardware arrangements and components
outside of a baseband modem processor can be used in
implementations, including RF-chains, power amplifiers, modulators,
buffers, interleavers, adders/summers, etc.
[0171] In this example, the processing system 1102 may be
implemented with a bus architecture, represented generally by the
bus 1106. The bus 1106 may include any number of interconnecting
buses and bridges depending on the specific application of the
processing system 1102 and the overall design constraints. The bus
1106 communicatively couples together various circuits, including
one or more processors (represented generally by the processor
1104), a memory 1108, and computer-readable media (represented
generally by the computer-readable medium 1110). The bus 1106 may
also link various other circuits such as timing sources,
peripherals, voltage regulators, and power management circuits,
which are well known in the art, and therefore, will not be
described any further.
[0172] A bus interface 1112 provides an interface between the bus
1106 and a transceiver 1114. The transceiver 1114 may be a wireless
transceiver. The transceiver 1114 may provide a means for
communicating with various other apparatus over a transmission
medium (e.g., air interface). The transceiver 1114 may further be
coupled to one or more antenna(s)/antenna array(s) (hereinafter
antenna 1116). In some examples, the transceiver 1114 and the
antenna 1116 may be configured to transmit and receive using
directional beamforming (e.g., using a single beam or a beam pair
link (BPL) on each of the uplink and downlink transmissions). The
bus interface 1112 further provides an interface between the bus
1106 and a user interface 1118 (e.g., keypad, display, touch
screen, speaker, microphone, control features, etc.). Of course,
such a user interface 1118 is optional and may be omitted in some
examples. In addition, the bus interface 1112 further provides an
interface between the bus 1106 and a power source 1120 of the
wireless communication apparatus 1100.
[0173] The processor 1104 is responsible for managing the bus 1106
and general processing, including the execution of software stored
on the computer-readable medium 1110. The software, when executed
by the processor 1104, causes the processing system 1102 to perform
the various functions described below for any particular apparatus.
The computer-readable medium 1110 and the memory 1108 may also be
used for storing data that is manipulated by the processor 1104
when executing software.
[0174] Software shall be construed broadly to mean instructions,
instruction sets, code, code segments, program code, programs,
subprograms, software modules, applications, software applications,
software packages, routines, subroutines, objects, executables,
threads of execution, procedures, functions, etc., whether referred
to as software, firmware, middleware, microcode, hardware
description language, or otherwise. The software may reside on the
computer-readable medium 1110. When executed by the processor 1104,
the software may cause the processing system 1102 to perform the
various processes and functions described herein for any particular
apparatus.
[0175] The computer-readable medium 1110 may be a non-transitory
computer-readable medium and may be referred to as a
computer-readable storage medium or a non-transitory
computer-readable medium. The non-transitory computer-readable
medium may store computer-executable code (e.g.,
processor-executable code). The computer-executable code may
include code for causing a computer (e.g., a processor) to
implement one or more of the functions described herein. A
non-transitory computer-readable medium includes, by way of
example, a magnetic storage device (e.g., hard disk, floppy disk,
magnetic strip), an optical disk (e.g., a compact disc (CD) or a
digital versatile disc (DVD)), a smart card, a flash memory device
(e.g., a card, a stick, or a key drive), a random access memory
(RAM), a read only memory (ROM), a programmable ROM (PROM), an
erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a
register, a removable disk, and any other suitable medium for
storing software and/or instructions that may be accessed and read
by a computer. The computer-readable medium 1110 may reside in the
processing system 1102, external to the processing system 1102, or
distributed across multiple entities including the processing
system 1102. The computer-readable medium 1110 may be embodied in a
computer program product or article of manufacture. By way of
example, a computer program product or article of manufacture may
include a computer-readable medium in packaging materials. In some
examples, the computer-readable medium 1110 may be part of the
memory 1108. Those skilled in the art will recognize how best to
implement the described functionality presented throughout this
disclosure depending on the particular application and the overall
design constraints imposed on the overall system.
[0176] In some aspects of the disclosure, the processor 1104 may
include communication and processing circuitry 1141 configured for
various functions, including, for example, communicating with a
scheduled entity (e.g., a wireless communication device, a UE), a
network core (e.g., a 5G core network), other scheduling entities,
or any other entity, such as, for example, local infrastructure or
an entity communicating with the wireless communication apparatus
1100 via the Internet, such as a network provider. In some
examples, the communication and processing circuitry 1141 may
include one or more hardware components that provide the physical
structure that performs processes related to wireless communication
(e.g., signal reception and/or signal transmission) and signal
processing (e.g., processing a received signal and/or processing a
signal for transmission). For example, the communication and
processing circuitry 1141 may include one or more transmit/receive
chains.
[0177] In some implementations where the communication involves
receiving information, the communication and processing circuitry
1141 may obtain information from a component of the wireless
communication apparatus 1100 (e.g., from the transceiver 1114 that
receives the information via radio frequency signaling or some
other type of signaling suitable for the applicable communication
medium), process (e.g., decode) the information, and output the
processed information. For example, the communication and
processing circuitry 1141 may output the information to another
component of the processor 1104, to the memory 1108, or to the bus
interface 1112. In some examples, the communication and processing
circuitry 1141 may receive one or more of: signals, messages, other
information, or any combination thereof. In some examples, the
communication and processing circuitry 1141 may receive information
via one or more channels. In some examples, the communication and
processing circuitry 1141 may include functionality for a means for
receiving. In some examples, the communication and processing
circuitry 1141 may include functionality for a means for
processing, including a means for demodulating, a means for
decoding, etc.
[0178] In some implementations where the communication involves
sending (e.g., transmitting) information, the communication and
processing circuitry 1141 may obtain information (e.g., from
another component of the processor 1104, the memory 1108, or the
bus interface 1112), process (e.g., modulate, encode, etc.) the
information, and output the processed information. For example, the
communication and processing circuitry 1141 may output the
information to the transceiver 1114 (e.g., that transmits the
information via radio frequency signaling or some other type of
signaling suitable for the applicable communication medium). In
some examples, the communication and processing circuitry 1141 may
send one or more of signals, messages, other information, or any
combination thereof. In some examples, the communication and
processing circuitry 1141 may send information via one or more
channels. In some examples, the communication and processing
circuitry 1141 may include functionality for a means for sending
(e.g., a means for transmitting). In some examples, the
communication and processing circuitry 1141 may include
functionality for a means for generating, including a means for
modulating, a means for encoding, etc. In some examples, the
communication and processing circuitry 1141 may be configured to
receive and process uplink traffic and uplink control messages
(e.g., similar to uplink traffic 116 and uplink control 118 of FIG.
1) and process and transmit downlink traffic and downlink control
messages (e.g., similar to downlink traffic 112 and downlink
control 114) via the antenna 1116 and the transceiver 1114.
[0179] In some examples, the communication and processing circuitry
1141 may further be configured to obtain downlink control
information (DCI) and uplink cancellation indication (ULCI)
messages that may be used to allocate resources defining uplink
channels to one or a group of scheduled entities, and to cancel at
least a portion of the allocated resources for the defined uplink
channels. The communication and processing circuitry 1141 may
further be configured to execute communication and processing
software 1151 stored on the computer-readable medium 1110 to
implement one or more functions described herein.
[0180] In some aspects of the disclosure, the processor 1104 may
include peak reduction tone (PRT) circuitry 1142 configured for
various functions, including, for example, obtaining (e.g.,
receiving via control signaling or otherwise) a set of resources
that includes a plurality of tones. According to some aspects, the
set of resources may include at least one of: a non-contiguous set
of resource blocks, or a non-contiguous set of subcarriers. The PRT
circuitry 1142 may further be configured, for example, to obtain a
predetermined sequence of peak reduction tones (PRTs). The
predetermined sequence of PRTs may correspond to a set of granted
resources including a plurality of tones. As used herein, the
phrases a "set of granted resources" and a "set of resources" are
used interchangeably herein, without regard to whether the
resources are granted or assigned. According to some aspects, the
wireless communication apparatus may be pre-configured with the
predetermined sequence of PRTs corresponding to the set of granted
resources including a plurality of tones.
[0181] In some examples, the PRT circuitry 1142 may obtain the
predetermined sequence of PRTs by at least one of: obtaining the
predetermined sequence of PRTs from the memory 1108 of the wireless
communication apparatus 1100, obtaining the predetermined sequence
of PRTs from a table (e.g., PRT sequence table 1122) that may be
stored in the memory 1108 of the wireless communication apparatus
1100, or constructing the predetermined sequence of PRTs from a
plurality of PRT-related functions 1124 that may be stored in the
memory 1108 of the wireless communication apparatus 1100. Examples
of PRT-related functions may include, without limitation, any one
or more of Equations 1-23 expressed herein.
[0182] In some examples, the PRT circuitry 1142 may obtain the
predetermined sequence of PRTs by: determining a number D,
corresponding to a ratio of a number of resource blocks (RBs) in
the set of resources to 60 RBs (e.g., granted or assigned resources
as used interchangeably herein), rounded up to a closest positive
integer, obtaining a set of marks of a Golomb ruler corresponding
to 1/D multiplied by the number of RBs in the set of resources,
constructing an initial sequence, r, equal to the PRT sequence
corresponding to the Golomb ruler, and interleaving r with D-1
copies of r to construct the predetermined sequence of PRTs. By way
of example, if the ratio of the number of RBs in the set of
resources to 60 RBs was equal to 1.1, the value of 1.1 rounded up
to the nearest positive integer would be equal to 2. In some
examples, Golomb rulers of order x, and the marks of the respective
Golomb rulers of order x, may be stored in a table, such as the
Golomb ruler table 1126. An example of an optimal Golomb ruler
table is provided as Table I herein.
[0183] According to some aspects, the PRT circuitry 1142 may
construct (e.g., obtain) the predetermined sequence of PRTs (e.g.,
PRTseq(i), where i={1, . . . , N} and N is an integer corresponding
to a total number of subcarriers in the set of resources (also
referred to herein as the set of granted resources)), based on:
[0184] for D=1: [0185] determining a square root, x, of the total
number of subcarriers in the set of resources, rounded up to a
closest positive integer; [0186] selecting a Golomb ruler of order
x, where marks on the Golomb ruler represent peak reduction tone
indices; and [0187] constructing the PRTseq(i) as a sequence of
zeros and ones of length equal to the total number of subcarriers,
wherein PRTseq(i) is equal to 1 at the peak reduction tone indices
and zero otherwise;
[0187] for .times. .times. D = 2 : .times. PRTseq .function. ( i )
= { r .function. ( i 2 ) .times. .times. if .times. .times. mod
.function. ( i , 2 ) = 0 r .function. ( i - 1 2 ) .times. .times.
if .times. .times. mod .function. ( i , 2 ) = 1 ; .times. for
.times. .times. D = 3 : .times. PRTseq .function. ( i ) = { r
.function. ( i 3 ) .times. .times. if .times. .times. mod
.function. ( i , 3 ) = 0 r .function. ( i - 1 3 ) .times. .times.
if .times. .times. mod .function. ( i , 3 ) = 1 r .function. ( i -
2 3 ) .times. .times. if .times. .times. mod .function. ( i , 3 ) =
2 ; .times. for .times. .times. D = 4 : .times. PRTseq .function. (
i ) = { r .function. ( i 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 0 r .function. ( i - 1 4 ) .times. .times.
if .times. .times. mod .function. ( i , 4 ) = 1 r .function. ( i -
2 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
2 r .function. ( i - 3 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 3 ; and .times. .times. for .times. .times.
D = 5 : .times. PRTseq .function. ( i ) = { r .function. ( i 5 )
.times. .times. if .times. .times. mod .function. ( i , 5 ) = 0 r
.function. ( i - 1 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 1 r .function. ( i - 2 5 ) .times. .times.
if .times. .times. mod .function. ( i , 5 ) = 2 r .function. ( i -
3 5 ) .times. .times. if .times. .times. mod .function. ( i , 5 ) =
3 r .function. ( i - 4 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 4 . ##EQU00014##
[0188] In some examples, the PRT circuitry 1142 may include one or
more hardware components that provide the physical structure that
performs processes related to obtaining the set of granted
resources that includes the plurality of tones and obtaining the
predetermined sequence of peak reduction tones (PRTs) corresponding
to the set of granted resources. The PRT circuitry 1142 may further
be configured to execute peak reduction tone software 1152 stored
on the computer-readable medium 1110 to implement one or more
functions described herein.
[0189] In some aspects of the disclosure, the processor 1104 may
include mapping circuitry 1143 configured for various functions,
including, for example, mapping a set of data to a first subset of
the plurality of tones (in the set of resources, also referred to
as the set of granted resources) outside of the predetermined
sequence of PRTs, and mapping a set of PRTs to a second subset of
the plurality of tones within the predetermined sequence of PRTs.
According to some aspects, only the first subset of the plurality
of tones is intended to be decoded. In some examples, the mapping
circuitry 1143 may include one or more hardware components that
provide the physical structure that performs processes related to
performing the mapping of the set of data to the first subset of
the plurality of tones outside of the predetermined sequence of
PRTs, and the mapping a set of PRTs to the second subset of the
plurality of tones within the predetermined sequence of PRTs. The
mapping circuitry 1143 may further be configured to execute mapping
software 1153 stored on the computer-readable medium 1110 to
implement one or more functions described herein.
[0190] In some aspects of the disclosure, the processor 1104 may
include cancelation and peak shifting circuitry 1144 configured for
various functions, including, for example, canceling at least one
peak of a time domain representation of the first subset of the
plurality of tones using a time domain representation of the second
subset of the plurality of tones. According to some aspects, the
canceling of the at least one peak of the time domain
representation of the first subset of the plurality of tones using
a time domain representation of the second subset of the plurality
of tones may include shifting a phase and scaling an amplitude of
the time domain representation of the second subset of the
plurality of tones to align a target peak of the time domain
representation of the first subset of the plurality of tones with a
peak of the shifted and scaled time domain representation of the
second subset of the plurality of tones, subtracting the shifted
and scaled time domain representation of the second subset of the
plurality of tones from the time domain representation of the first
subset of the plurality of tones to obtain a time domain
representation of the plurality of tones, and repeating the
shifting, the scaling, and the subtracting until all peaks of the
time domain representation of the plurality of tones are less than
a predefined threshold. In some examples, the cancelation and peak
shifting circuitry 1144 may include one or more hardware components
that provide the physical structure that performs processes related
to performing the canceling at least the one peak of the time
domain representation of the first subset of the plurality of tones
using the time domain representation of the second subset of the
plurality of tones. The cancelation and peak shifting circuitry
1144 may further be configured to execute peak cancelation software
1154 stored on the computer-readable medium 1110 to implement one
or more functions described herein.
[0191] In some aspects of the disclosure, the processor 1104 may
include waveform transmitting circuitry 1145 configured for various
functions, including, for example, transmitting a transmitted
waveform comprising the first subset of the plurality of tones and
the second subset of the plurality of tones (e.g., the plurality of
tones). In some examples, the waveform transmitting circuitry 1145
may include one or more hardware components that provide the
physical structure that performs processes related to performing
the transmitting of the transmitted waveform comprising the first
subset of the plurality of tones and the second subset of the
plurality of tones. The waveform transmitting circuitry 1145 may
further be configured to execute waveform transmitting software
1155 stored on the computer-readable medium 1110 to implement one
or more functions described herein.
[0192] FIG. 12 is a flow chart illustrating an exemplary process
1200 (e.g., a method of wireless communication) at a wireless
communication apparatus (e.g., a scheduling entity or a scheduled
entity) in a wireless communication network according to some
aspects of the disclosure. The wireless communication apparatus may
obtain a predetermined sequence of peak reduction tones (PRTs),
which may correspond to a set of (granted) resources that includes
one or more resource blocks, each including a plurality of tones
(e.g., 12 tones or subcarriers). In one example, the predetermined
sequence of PRTs may correspond to the marks on a Golomb ruler
having an order that is a function of a total number of tones in
the set of resources. The wireless communication apparatus may map
a set of data (e.g., control and/or traffic) to a first subset of
the plurality of tones outside of the predetermined sequence of
PRTs and may map a set of PRTs to a second subset of the plurality
of tones within the predetermined sequence of PRTs. The wireless
communication apparatus may cancel at least one peak of a time
domain representation of the first subset of the plurality of tones
using a time domain representation of the second subset of the
plurality of tones and may transmit a transmitted waveform
comprising the first subset of the plurality of tones and the
second subset of the plurality of tones (e.g., the plurality of
tones). Implementation of the process may reduce the PAPR of
transmitted signals. As described below, some or all illustrated
features may be omitted in a particular implementation within the
scope of the present disclosure, and some illustrated features may
not be required for all implementations. In some examples, the
process 1200 may be carried out by the wireless communication
apparatus 1100 (e.g., a scheduling entity or a scheduled entity)
illustrated in FIG. 11. In some examples, the process 1200 may be
carried out by any suitable apparatus or means for carrying out the
functions or algorithms described herein.
[0193] At block 1202, the wireless communication apparatus may
obtain a predetermined sequence of peak reduction tones (PRTs)
corresponding to a set of resources (also referred to as a set of
granted resources herein) that include a plurality of tones. In
some examples, the set of resources may include at least one of: a
non-contiguous set of resource blocks, or a non-contiguous set of
subcarriers (the terms "tones" and "subcarriers" are used
interchangeably herein, the terms "resources" and "granted
resources" are used interchangeably herein). The resources may be
OFDM resources as illustrated in the examples of FIGS. 3-10. In
some examples, the predetermined sequence of PRTs may be a Golomb
ruler having an order that is a function of a total number of tones
in the set of resources. A table of exemplary known optimal Golomb
rulers of orders 1-27 is provided as Table I, above. For example,
the PRT circuitry 1142, shown and described above in connection
with FIG. 11, may provide a means for obtaining the predetermined
sequence of peak reduction tones (PRTs) that correspond to the set
of resources that includes the plurality of tones.
[0194] In some examples, the predetermined sequence of PRTs may be
obtained by at least one of: obtaining the predetermined sequence
of PRTs from a memory of the wireless communication apparatus,
obtaining the predetermined sequence of PRTs from a table stored in
the memory of the wireless communication apparatus, or constructing
the predetermined sequence of PRTs from a plurality of PRT-related
functions stored in the memory of the wireless communication
apparatus.
[0195] In some examples, the predetermined sequence of PRTs may be
obtained by determining a number D, corresponding to a ratio of a
number of resource blocks (RBs) in the set of resources to 60 RBs
(also referred to as a set of granted resources herein), rounded up
to the closest positive integer, obtaining a set of marks of a
Golomb ruler corresponding to 1/D multiplied by the number of RBs
in the set of resources, constructing an initial sequence, r, equal
to the PRT sequence corresponding to the Golomb ruler), and
interleaving r with D-1 copies of r to construct the predetermined
sequence of PRTs.
[0196] In other examples, the predetermined sequence of PRTs may be
obtained by determining a number D, corresponding to a ratio of a
number of resource blocks (RBs) in the set of resources to 60 RBs
(also referred to as a set of granted resources herein), rounded up
to the closest positive integer, obtaining a set of marks of a
Golomb ruler corresponding to 1/D multiplied by the number of RBs
in the set of resources, constructing a sequence, r, based on the
set of marks of the Golomb ruler, and constructing the
predetermined sequence of PRTs (PRTseq(i)), where i={1, . . . , N}
and Nis an integer corresponding to a total number of subcarriers
in the set of resources, based on:
[0197] for D=1: [0198] determining a square root, x, of the total
number of subcarriers in the set of resources, rounded up to a
closest positive integer; [0199] selecting a Golomb ruler of order
x, where marks on the Golomb ruler represent peak reduction tone
indices; and [0200] constructing the PRTseq(i) as a sequence of
zeros and ones of length equal to the total number of subcarriers,
wherein PRTseq(i) is equal to 1 at the peak reduction tone indices
and zero otherwise;
[0200] for .times. .times. D = 2 : .times. PRTseq .function. ( i )
= { r .function. ( i 2 ) .times. .times. if .times. .times. mod
.function. ( i , 2 ) = 0 r .function. ( i - 1 2 ) .times. .times.
if .times. .times. mod .function. ( i , 2 ) = 1 ; .times. for
.times. .times. D = 3 : .times. PRTseq .function. ( i ) = { r
.function. ( i 3 ) .times. .times. if .times. .times. mod
.function. ( i , 3 ) = 0 r .function. ( i - 1 3 ) .times. .times.
if .times. .times. mod .function. ( i , 3 ) = 1 r .function. ( i -
2 3 ) .times. .times. if .times. .times. mod .function. ( i , 3 ) =
2 ; .times. for .times. .times. D = 4 : .times. PRTseq .function. (
i ) = { r .function. ( i 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 0 r .function. ( i - 1 4 ) .times. .times.
if .times. .times. mod .function. ( i , 4 ) = 1 r .function. ( i -
2 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
2 r .function. ( i - 3 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 3 ; and .times. .times. for .times. .times.
D = 5 : .times. PRTseq .function. ( i ) = { r .function. ( i 5 )
.times. .times. if .times. .times. mod .function. ( i , 5 ) = 0 r
.function. ( i - 1 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 1 r .function. ( i - 2 5 ) .times. .times.
if .times. .times. mod .function. ( i , 5 ) = 2 r .function. ( i -
3 5 ) .times. .times. if .times. .times. mod .function. ( i , 5 ) =
3 r .function. ( i - 4 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 4 . ##EQU00015##
[0201] At block 1204, the wireless communication apparatus may map
a set of data to a first subset of the plurality of tones outside
of the predetermined sequence of PRTs. At block 1206, the wireless
communication apparatus may map a set of PRTs to a second subset of
the plurality of tones within the predetermined sequence of PRTs.
Examples of mappings of the first subset of the plurality of tones
and the second subset of the predetermined sequence of PRTS may be
illustrated in FIGS. 5 and 9 and their related text. For example,
the mapping circuitry 1143, shown and described above in connection
with FIG. 11, may provide the means for mapping the set of data to
the first subset of the plurality of tones outside of the
predetermined sequence of PRTs and the means for mapping the set of
PRTs to the second subset of the plurality of tones within the
predetermined sequence of PRTs.
[0202] At block 1208, the wireless communication apparatus may
cancel at least one peak of a time domain representation of the
first subset of the plurality of tones using a time domain
representation of the second subset of the plurality of tones.
According to some aspects, the canceling of the at least one peak
of the time domain representation of the first subset of the
plurality of tones using the time domain representation of the
second subset of the plurality of tones may further include
shifting a phase and scaling an amplitude of the time domain
representation of the second subset of the plurality of tones to
align a target peak of the first time domain representation of the
plurality of tones with a peak of the shifted and scaled time
domain representation of the second subset of the plurality of
tones, subtracting the shifted and scaled time domain
representation of the second subset of the plurality of tones from
the time domain representation of the first subset of the plurality
of tones to obtain a time domain representation of the plurality of
tones, and repeating the shifting, the scaling, and the subtracting
until all peaks of a time domain representation of the plurality of
tones are less than a predefined threshold. An example of
cancelation is described in connection with FIG. 6 and its
associated text. The benefit of cancelation and peak shifting in
terms of CCDF of PAPR per resource block and per tone,
respectively, is illustrated in FIGS. 10A and 10B and described in
their associated text. For example, the cancelation and peak
shifting circuitry 1144, shown and described above in connection
with FIG. 11, may provide the means for canceling at least one peak
of the time domain representation of the first subset of the
plurality of tones using the time domain representation of the
second subset of the plurality of tones. The cancelation and peak
shifting circuitry 1144 may also provide the means for shifting a
phase and scaling an amplitude of the time domain representation of
the second subset of the plurality of tones to align a target peak
of the time domain representation of the first plurality of tones
with a peak of the shifted and scaled time domain representation of
the second subset of the plurality of tones, a means for
subtracting the shifted and scaled time domain representation of
the second subset of the plurality of tones from the time domain
representation of the first subset of the plurality of tones to
obtain a time domain representation of the plurality of tones, and
a means for repeating the shifting, the scaling, and the
subtracting until all peaks of the time domain representation of
the plurality of tones are less than a predefined threshold.
Transformations between frequency domain representations of tones
and time domain representations of tones may be accomplished by any
method known to those of skill in the art. For example, a fast
Fourier transform may be used to transform from the time domain to
the frequency domain.
[0203] At block 1210, the wireless communication apparatus may
transmit a transmitted waveform including the first subset of the
plurality of tones and the second subset of the plurality of tones
(e.g., the plurality of tones). For example, the waveform
transmitting circuitry 1145, in cooperation with the transceiver
1114 and antenna(s)/antenna array(s) 1114, as shown and described
above in connection with FIG. 11, may provide a means for
transmitting a transmitted waveform including the first subset of
the plurality of tones and the second subset of the plurality of
tones.
[0204] FIG. 13 is a flow chart illustrating another exemplary
process 1300 (e.g., a method) at a wireless communication apparatus
(e.g., a scheduling entity or a scheduled entity) for wireless
communication according to some aspects of the disclosure.
According to some aspects, a set of resources (also referred to as
a set of granted resources herein) may be expressed as a number
(e.g., a quantity) of resource blocks (RBs). At block 1302, the
wireless communication apparatus may determine a number D,
corresponding to a ratio of the number of RBs in the set of
resources to 60 RBs, rounded up to the closest positive integer.
For example, the communication and processing circuitry 1141, shown
and described above in connection with FIG. 11, may provide the
means for determining the number D, corresponding to the ratio of
the number of RBs in the set of resources to 60 RBs, rounded up to
the closest positive integer.
[0205] At block 1304, the wireless communication apparatus may
obtain a set of marks of a Golomb ruler (e.g., an optimal Golomb
ruler) corresponding to 1/D multiplied by the number of RBs in the
set of resources. In one example, 1/D may represent a number (e.g.,
a quantity) of RBs, and the order may be a function of the number
of tones in the quantity of RBs (e.g., order=square root of the
number of tones). For example, the PRT circuitry 1142, shown and
described above in connection with FIG. 11, may provide the means
for obtaining a set of marks of a Golomb ruler corresponding to 1/D
multiplied by the number of RBs in the set of resources.
[0206] At block 1306, the wireless communication apparatus may
construct (e.g., obtain) an initial sequence, r, equal to a PRT
sequence corresponding to the Golomb ruler. For example, the PRT
circuitry 1142, shown and described above in connection with FIG.
11, may provide the means for constructing the initial sequence, r,
equal to the PRT sequence corresponding to the Golomb ruler.
[0207] At block 1310, the wireless communication apparatus may
interleave r with D-1 copies of r to construct the predetermined
sequence of PRTs. For example, the communication and processing
circuitry 1141, shown and described above in connection with FIG.
11, may provide the means for interleaving r with D-1 copies of r
to construct the predetermined sequence of PRTs.
[0208] According to yet other aspects, prior to transmitting a
transmitted waveform comprising the first subset of the plurality
of tones and the second subset of the plurality of tones (e.g., the
plurality of tones), the wireless communication apparatus may
further shift a phase and scale an amplitude of a time domain
representation of the second subset of the plurality of tones to
align a target peak of the time domain representation of the first
plurality of tones with a peak of the shifted and scaled time
domain representation of the second subset of the plurality of
tones, subtracting the shifted and scaled time domain
representation of the second subset of the plurality of tones from
the time domain representation of the first subset of the plurality
of tones to obtain a time domain representation of the plurality of
tones, and repeating the shifting, the scaling, and the subtracting
until all peaks of the time domain representation of the plurality
of tones are less than a predefined threshold. For example, the
communication and processing circuitry 1141, the PRT circuitry
1142, and/or the cancelation and peak shifting circuitry 1144 shown
and described above in connection with FIG. 11, may provide the
means for shifting, the means for subtracting, and/or the means for
repeating. Still further, the waveform transmitting circuitry 1145
may provide the means for transmitting the transmitted waveform as
described herein.
[0209] Of course, in the above examples, the circuitry included in
the processor 1104 is merely provided as an example, and other
means for carrying out the described functions may be included
within various aspects of the present disclosure, including but not
limited to the instructions stored in the computer-readable medium
1110, or any other suitable apparatus or means described in any one
of the FIGS. 1, 2, and/or 11, and utilizing, for example, the
processes and/or algorithms described herein in relation to FIGS.
4-10, 12, and/or 13.
[0210] The following provides an overview of the present
disclosure:
[0211] Aspect 1: A method of wireless communication in a wireless
communication network, the method comprising, at a wireless
communication apparatus: obtaining a predetermined sequence of peak
reduction tones (PRTs) corresponding to a set of granted resources
comprised of a plurality of tones, mapping a set of data to a first
subset of the plurality of tones outside of the predetermined
sequence of PRTs, mapping a set of PRTs to a second subset of the
plurality of tones within the predetermined sequence of PRTs,
canceling at least one peak of a time domain representation of the
first subset of the plurality of tones using a time domain
representation of the second subset of the plurality of tones, and
transmitting a transmitted waveform comprising the first subset of
the plurality of tones and the second subset of the plurality of
tones.
[0212] Aspect 2: The method of aspect 1, wherein only the first
subset of the plurality of tones is intended to be decoded.
[0213] Aspect 3: The method of aspect 1 or 2, wherein the wireless
communication apparatus is pre-configured with the predetermined
sequence of PRTs corresponding to the set of granted resources.
[0214] Aspect 4: The method of any of aspects 1 through 3, wherein
the set of granted resources comprise at least one of: a
non-contiguous set of resource blocks, or a non-contiguous set of
subcarriers.
[0215] Aspect 5: The method of any of aspects 1 through 4, further
comprising: obtaining the predetermined sequence of PRTs by
obtaining a Golomb ruler having an order that is a function of a
total number of tones in the set of granted resources.
[0216] Aspect 6: The method of any of aspects 1 through 4, further
comprising obtaining the predetermined sequence of PRTs by at least
one of: obtaining the predetermined sequence of PRTs from a memory
of the wireless communication apparatus, obtaining the
predetermined sequence of PRTs from a table stored in the memory of
the wireless communication apparatus, or constructing the
predetermined sequence of PRTs from a plurality of PRT-related
functions stored in the memory of the wireless communication
apparatus.
[0217] Aspect 7: The method of any of aspects 1 through 6, wherein
the canceling the at least one peak of the time domain
representation of the first subset of the plurality of tones using
the time domain representation of the second subset of the
plurality of tones, further comprises: shifting a phase and scaling
an amplitude of the time domain representation of the second subset
of the plurality of tones to align a target peak of the time domain
representation of the first subset of the plurality of tones with a
peak of the shifted and scaled time domain representation of the
second subset of the plurality of tones, subtracting the shifted
and scaled time domain representation of the second subset of the
plurality of tones from the time domain representation of the first
subset of the plurality of tones to obtain a time domain
representation of the plurality of tones; and repeating the
shifting, the scaling, and the subtracting until all peaks of the
time domain representation of the plurality of tones are less than
a predefined threshold.
[0218] Aspect 8: The method of any of aspects 1 through 4 and 7,
further comprising, obtaining the predetermined sequence of PRTs
by: determining a number D, corresponding to a ratio of a number of
resource blocks (RBs) in the set of granted resources to 60 RBs,
rounded up to a closest positive integer, obtaining a set of marks
of a Golomb ruler corresponding to 1/D multiplied by the number of
RBs in the set of granted resources, constructing an initial
sequence, r, equal to an initial PRT sequence corresponding to the
Golomb ruler; and interleaving r with D-1 copies of r to construct
the predetermined sequence of PRTs.
[0219] Aspect 9: The method of any of aspects 1 through 4 and 7,
further comprising, obtaining the predetermined sequence of PRTs
by: determining a number D, corresponding to a ratio of a number of
resource blocks (RBs) in the set of granted resources to 60 RBs,
rounded up to a closest positive integer, obtaining a set of marks
of a Golomb ruler having an index corresponding to 1/D multiplied
by the number of RBs in the set of granted resources, constructing
a sequence, r, based on the set of marks of the Golomb ruler; and
constructing the predetermined sequence of PRTs (PRTseq(i)),
wherein i={1, . . . , N} and N is an integer corresponding to a
total number of subcarriers in the set of granted resources, based
on:
[0220] for D=1:
[0221] determining a square root, x, of the total number of
subcarriers in the set of granted resources, rounded up to the
closest positive integer, selecting a Golomb ruler of order x,
where marks on the Golomb ruler represent peak reduction tone
indices; and
constructing the PRTseq(i) as a sequence of zeros and ones of
length equal to the total number of subcarriers, wherein PRTseq(i)
is equal to 1 at the peak reduction tone indices and zero
otherwise,
for .times. .times. D = 2 : .times. PRTseq .function. ( i ) = { r
.function. ( i 2 ) .times. .times. if .times. .times. mod
.function. ( i , 2 ) = 0 r .function. ( i - 1 2 ) .times. .times.
if .times. .times. mod .function. ( i , 2 ) = 1 , for .times.
.times. D = 3 : .times. PRTseq .function. ( i ) = { r .function. (
i 3 ) .times. .times. if .times. .times. mod .function. ( i , 3 ) =
0 r .function. ( i - 1 3 ) .times. .times. if .times. .times. mod
.function. ( i , 3 ) = 1 r .function. ( i - 2 3 ) .times. .times.
if .times. .times. mod .function. ( i , 3 ) = 2 , for .times.
.times. D = 4 : .times. PRTseq .function. ( i ) = { r .function. (
i 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
0 r .function. ( i - 1 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 1 r .function. ( i - 2 4 ) .times. .times.
if .times. .times. mod .function. ( i , 4 ) = 2 r .function. ( i -
3 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
3 ; and .times. .times. for .times. .times. D = 5 : .times. PRTseq
.function. ( i ) = { r .function. ( i 5 ) .times. .times. if
.times. .times. mod .function. ( i , 5 ) = 0 r .function. ( i - 1 5
) .times. .times. if .times. .times. mod .function. ( i , 5 ) = 1 r
.function. ( i - 2 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 2 r .function. ( i - 3 5 ) .times. .times.
if .times. .times. mod .function. ( i , 5 ) = 3 r .function. ( i -
4 5 ) .times. .times. if .times. .times. mod .function. ( i , 5 ) =
4 . ##EQU00016##
[0222] Aspect 10: A wireless communication apparatus in a wireless
communication network, comprising: a wireless transceiver, a
memory, and a processor coupled to the wireless transceiver and the
memory, wherein the processor and the memory are configured to:
obtain a predetermined sequence of peak reduction tones (PRTs)
corresponding to a set of granted resources comprised of a
plurality of tones, map a set of data to a first subset of the
plurality of tones outside of the predetermined sequence of PRTs,
map a set of PRTs to a second subset of the plurality of tones
within the predetermined sequence of PRTs, cancel at least one peak
of a time domain representation of the first subset of the
plurality of tones using a time domain representation of the second
subset of the plurality of tones, and transmit a transmitted
waveform comprising the first subset of the plurality of tones and
the second subset of the plurality of tones.
[0223] Aspect 11: The wireless communication apparatus of aspect
10, wherein only the first subset of the plurality of tones is
intended to be decoded.
[0224] Aspect 12: The wireless communication apparatus of aspect 10
or 11, wherein the wireless communication apparatus is
pre-configured with the predetermined sequence of PRTs associated
with the set of granted resources.
[0225] Aspect 13: The wireless communication apparatus of any of
aspects 10 through 12, wherein the set of granted resources
comprises at least one of: a non-contiguous set of resource blocks,
or a non-contiguous set of subcarriers.
[0226] Aspect 14: The wireless communication apparatus of any of
aspects 10 through 13, wherein the processor and the memory are
further configured to obtain the predetermined sequence of PRTs by
obtaining an Golomb ruler having an order that is a function of a
total number of tones in the set of granted resources.
[0227] Aspect 15: The wireless communication apparatus of any of
aspects 10 through 13, wherein the processor and the memory are
further configured to obtain the predetermined sequence of PRTs by
being further configured to at least one of: obtain the
predetermined sequence of PRTs from a memory of the wireless
communication apparatus, obtain the predetermined sequence of PRTs
from a table stored in the memory of the wireless communication
apparatus, or construct the predetermined sequence of PRTs from a
plurality of PRT-related functions stored in the memory of the
wireless communication apparatus.
[0228] Aspect 16: The wireless communication apparatus of aspects
10 through 15, wherein the processor and the memory are configured
to cancel the at least one peak of the time domain representation
of the first subset of the plurality of tones using the time domain
representation of the second subset of the plurality of tones by
being further configured to: shift a phase and scale an amplitude
of the time domain representation of the second subset of the
plurality of tones to align a target peak of the time domain
representation of the first subset of the plurality of tones with a
peak of the shifted and scaled time domain representation of the
second subset of the plurality of tones; subtract the shifted and
scaled time domain representation of the second subset of the
plurality of tones from the time domain representation of the first
subset of the plurality of tones to obtain a time domain
representation of the plurality of tones, and repeat the shifting,
the scaling, and the subtracting until all peaks of the time domain
representation of the plurality of tones are less than a predefined
threshold.
[0229] Aspect 17: The wireless communication apparatus of any of
aspects 10 through 13 and 16, wherein the processor and the memory
are configured to obtain the predetermined sequence of PRTs by
being further configured to: determine a number D, corresponding to
a ratio of a number of resource blocks (RBs) in the set of granted
resources to 60 RBs, rounded up to a closest positive integer,
obtain a set of marks of a Golomb ruler having an index
corresponding to 1/D multiplied by the number of RBs in the set of
granted resources, construct an initial sequence, r, equal to an
initial PRT sequence corresponding to the Golomb ruler, and
interleave r with D-1 copies of r to construct the predetermined
sequence of PRTs.
[0230] Aspect 18: The wireless communication apparatus of any of
aspects 10 through 13 and 16, wherein the processor and the memory
are configured to obtain the predetermined sequence of PRTs by
being further configured to: determine a number D, corresponding to
a ratio of a number of resource blocks (RBs) in the set of granted
resources to 60 RBs, rounded up to a closest positive integer,
obtain a set of marks of a Golomb ruler corresponding to 1/D
multiplied by the number of RBs in the set of granted resources,
construct a sequence, r, based on the set of marks of the Golomb
ruler; and construct the predetermined sequence of PRTs
(PRTseq(i)), wherein i={1, . . . , N} and N is an integer
corresponding to a total number of subcarriers in the set of
granted resources, based on:
[0231] for D=1:
[0232] determine a square root, x, of the total number of
subcarriers in the set of granted resources, rounded up to the
closest positive integer, select a Golomb ruler of order x, where
marks on the Golomb ruler represent peak reduction tone indices;
and construct the PRTseq(i), as a sequence of zeros and ones of
length equal to the total number of subcarriers, wherein PRTseq(i)
is equal to 1 at the peak reduction tone indices and zero
otherwise,
for .times. .times. D = 2 : .times. PRTseq .function. ( i ) = { r
.function. ( i 2 ) .times. .times. if .times. .times. mod
.function. ( i , 2 ) = 0 r .function. ( i - 1 2 ) .times. .times.
if .times. .times. mod .function. ( i , 2 ) = 1 , for .times.
.times. D = 3 : .times. PRTseq .function. ( i ) = { r .function. (
i 3 ) .times. .times. if .times. .times. mod .function. ( i , 3 ) =
0 r .function. ( i - 1 3 ) .times. .times. if .times. .times. mod
.function. ( i , 3 ) = 1 r .function. ( i - 2 3 ) .times. .times.
if .times. .times. mod .function. ( i , 3 ) = 2 , for .times.
.times. D = 4 : .times. PRTseq .function. ( i ) = { r .function. (
i 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
0 r .function. ( i - 1 4 ) .times. .times. if .times. .times. mod
.function. ( i , 4 ) = 1 r .function. ( i - 2 4 ) .times. .times.
if .times. .times. mod .function. ( i , 4 ) = 2 r .function. ( i -
3 4 ) .times. .times. if .times. .times. mod .function. ( i , 4 ) =
3 ; and .times. .times. for .times. .times. D = 5 : .times. PRTseq
.function. ( i ) = { r .function. ( i 5 ) .times. .times. if
.times. .times. mod .function. ( i , 5 ) = 0 r .function. ( i - 1 5
) .times. .times. if .times. .times. mod .function. ( i , 5 ) = 1 r
.function. ( i - 2 5 ) .times. .times. if .times. .times. mod
.function. ( i , 5 ) = 2 r .function. ( i - 3 5 ) .times. .times.
if .times. .times. mod .function. ( i , 5 ) = 3 r .function. ( i -
4 5 ) .times. .times. if .times. .times. mod .function. ( i , 5 ) =
4 . ##EQU00017##
[0233] Aspect 19: A wireless communication apparatus in a wireless
communication network, comprising: means for obtaining a
predetermined sequence of peak reduction tones (PRTs) corresponding
to a set of granted resources comprised of a plurality of tones,
means for mapping a set of data to a first subset of the plurality
of tones outside of the predetermined sequence of PRTs, means for
mapping a set of PRTs to a second subset of the plurality of tones
within the predetermined sequence of PRTs, means for canceling at
least one peak of a time domain representation of the first subset
of the plurality of tones using a time domain representation of the
second subset of the plurality of tones, and means for transmitting
a transmitted waveform comprising the first subset of the plurality
of tones and the second subset of the plurality of tones.
[0234] Aspect 20: The wireless communication apparatus of aspect
19, wherein only the first subset of the plurality of tones is
intended to be decoded.
[0235] Aspect 21: The wireless communication apparatus of aspect 19
or 20, wherein the means for obtaining the predetermined sequence
of PRTs further comprise at least one of: means for obtaining the
predetermined sequence of PRTs from a memory of the wireless
communication apparatus, means for obtaining the predetermined
sequence of PRTs from a table stored in the memory of the wireless
communication apparatus, or means for constructing the
predetermined sequence of PRTs from a plurality of PRT-related
functions stored in the memory of the wireless communication
apparatus.
[0236] 22: The wireless communication apparatus of any of aspects
19 through 21, wherein the means for canceling at least one peak of
the time domain representation of the first subset of the plurality
of tones using the time domain representation of the second subset
of the plurality of tones further comprises: means for shifting a
phase and scaling an amplitude of the time domain representation of
the second subset of the plurality of tones to align a target peak
of the time domain representation of the first subset of the
plurality of tones with a peak of the shifted and scaled time
domain representation of the second subset of the plurality of
tones, means for subtracting the shifted and scaled time domain
representation of the second subset of the plurality of tones from
the time domain representation of the first subset of the plurality
of tones to obtain a time domain representation of the plurality of
tones, and means for repeating the shifting, the scaling, and the
subtracting until all peaks of the time domain representation of
the plurality of tones are less than a predefined threshold.
[0237] Aspect 23: An article of manufacture for use by a wireless
communication apparatus in a wireless communication network, the
article comprising: a non-transitory computer-readable medium
having stored therein instructions executable by one or more
processors of the wireless communication apparatus to: obtain a
predetermined sequence of peak reduction tones (PRTs) corresponding
to a set of granted resources comprised of a plurality of tones,
map a set of data to a first subset of the plurality of tones
outside of the predetermined sequence of PRTs, map a set of PRTs to
a second subset of the plurality of tones within the predetermined
sequence of PRTs, cancel at least one peak of a time domain
representation of the first subset of the plurality of tones using
a time domain representation of the second subset of the plurality
of tones, and transmit a transmitted waveform comprising the first
subset of the plurality of tones and the second subset of the
plurality of tones.
[0238] Aspect 24: The article of manufacture of aspect 23, wherein
only the first subset of the plurality of tones is intended to be
decoded.
[0239] Aspect 25: The article of manufacture of aspect 23 or 24,
wherein the instructions executable by one or more processors of
the wireless communication apparatus further comprises instructions
to obtain the predetermined sequence of PRTs by at least one of:
obtaining the predetermined sequence of PRTs from a memory of the
wireless communication apparatus, obtaining the predetermined
sequence of PRTs from a table stored in the memory of the wireless
communication apparatus, or constructing the predetermined sequence
of PRTs from a plurality of PRT-related functions stored in the
memory of the wireless communication apparatus.
[0240] Aspect 26: The article of manufacture of any of aspects 23
through 25, wherein the instructions executable by one or more
processors of the wireless communication apparatus to cancel the at
least one peak of the time domain representation of the first
subset of the plurality of tones using the time domain
representation of the second subset of the plurality of tones,
further comprises instructions to: shift a phase and scale an
amplitude of the time domain representation of the second subset of
the plurality of tones to align a target peak of the time domain
representation of the first subset of the plurality of tones with a
peak of the shifted and scaled time domain representation of the
second subset of the plurality of tones, subtract the shifted and
scaled time domain representation of the second subset of the
plurality of tones from the time domain representation of the first
subset of the plurality of tones to obtain a time domain
representation of the plurality of tones, and repeat the shifting,
the scaling, and the subtracting until all peaks of the time domain
representation of the plurality of tones are less than a predefined
threshold.
[0241] Several aspects of a wireless communication network have
been presented with reference to an exemplary implementation. As
those skilled in the art will readily appreciate, various aspects
described throughout this disclosure may be extended to other
telecommunication systems, network architectures and communication
standards.
[0242] By way of example, various aspects may be implemented within
other systems defined by 3GPP, such as Long-Term Evolution (LTE),
the Evolved Packet System (EPS), the Universal Mobile
Telecommunication System (UMTS), and/or the Global System for
Mobile (GSM). Various aspects may also be extended to systems
defined by the 3rd Generation Partnership Project 2 (3GPP2), such
as CDMA 2000 and/or Evolution-Data Optimized (EV-DO). Other
examples may be implemented within systems employing IEEE 802.11
(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB),
Bluetooth, and/or other suitable systems. The actual
telecommunication standard, network architecture, and/or
communication standard employed will depend on the specific
application and the overall design constraints imposed on the
system.
[0243] Within the present disclosure, the word "exemplary" is used
to mean "serving as an example, instance, or illustration." Any
implementation or aspect described herein as "exemplary" is not
necessarily to be construed as preferred or advantageous over other
aspects of the disclosure. Likewise, the term "aspects" does not
require that all aspects of the disclosure include the discussed
feature, advantage, or mode of operation. The term "coupled" is
used herein to refer to the direct or indirect coupling between two
objects. For example, if object A physically touches object B, and
object B touches object C, then objects A and C may still be
considered coupled to one another--even if they do not directly
physically touch each other. For instance, a first object may be
coupled to a second object even though the first object is never
directly physically in contact with the second object. The terms
"circuit" and "circuitry" are used broadly, and intended to include
both hardware implementations of electrical devices and conductors
that, when connected and configured, enable the performance of the
functions described in the present disclosure, without limitation
as to the type of electronic circuits, as well as software
implementations of information and instructions that, when executed
by a processor, enable the performance of the functions described
in the present disclosure.
[0244] One or more of the components, steps, features and/or
functions illustrated in FIGS. 1-13 may be rearranged and/or
combined into a single component, step, feature, or function or
embodied in several components, steps, or functions. Additional
elements, components, steps, and/or functions may also be added
without departing from novel features disclosed herein. The
apparatus, devices, and/or components illustrated in FIGS. 1-13 may
be configured to perform one or more of the methods, features, or
steps described herein. The novel algorithms described herein may
also be efficiently implemented in software and/or embedded in
hardware.
[0245] It is to be understood that the specific order or hierarchy
of steps in the methods disclosed is an illustration of exemplary
processes. Based upon design preferences, it is understood that the
specific order or hierarchy of steps in the methods may be
rearranged. The accompanying method claims present elements of the
various steps in a sample order and are not meant to be limited to
the specific order or hierarchy presented unless specifically
recited therein.
[0246] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but are
to be accorded the full scope consistent with the language of the
claims, wherein reference to an element in the singular is not
intended to mean "one and only one" unless specifically so stated,
but rather "one or more." Unless specifically stated otherwise, the
term "some" refers to one or more. A phrase referring to "at least
one of" a list of items refers to any combination of those items,
including single members. As an example, "at least one of: a, b, or
c" is intended to cover: a; b; c; a and b; a and c; b and c; and a,
b and c. The construct A and/or B is intended to cover: A; B; and A
and B. The word "obtain" as used herein may mean, for example,
acquire, calculate, construct, derive, determine, receive, and/or
retrieve. The preceding list is exemplary and not limiting. All
structural and functional equivalents to the elements of the
various aspects described throughout this disclosure that are known
or later come to be known to those of ordinary skill in the art are
expressly incorporated herein by reference and are intended to be
encompassed by the claims. Moreover, nothing disclosed herein is
intended to be dedicated to the public regardless of whether such
disclosure is explicitly recited in the claims. No claim element is
to be construed under the provisions of 35 U.S.C. .sctn. 112(f)
unless the element is expressly recited using the phrase "means
for" or, in the case of a method claim, the element is recited
using the phrase "step for."
* * * * *